Dodge SRT Forum banner

1300CC injectors (problem)

7K views 79 replies 7 participants last post by  HybridKid 
#1 ·
A little background..

2004 w/50k miles
Plugs NGK 3306 (new)
Coil pack MOPAR (new)
Wires Granatelli (new)
AGP WGA
PCM boost control
Stage 2 injectors and supporting sensors
Straight pipes
AGP Hard pipes
BFMIC
solid motor mounts
Stock fuel pump
Stock fuel rail.

Recently I started observing that everyone once in a while my skittle would let out a rather strange backfire while cruising down the highway. I mean a loud BOOM that could be felt in the floor. Not too long after that I started getting a misfire code on cylinder #4 .. I replaced the CP (mopar), wires (Granatelli), plugs (NGK 3306) all the things that I had every reason to suspect could be the issue..

While the car got stronger, the misfire code persisted. So I swapped the injectors around and the problem followed. I swapped #4 with #3 and the misfires moved to #3 . (Stage 2 injectors)

So after pricing things out I decided to get 1300CC injectors and a couple tunes..

I installed the new injectors.
Disconnected the battery for 5 mins.
Installed the base tune.

I was on the base tune, and driving around to reset fuel trim/curve settings that I had previously erased. It was running and idling fine, not a single sign of trouble. When I stopped to wait for my kid to get out of a school function it started mis-firing and threw a code BANK 1 RICH.. I went through many trouble shooting steps and no matter what I did it got persistently worse. I received an updated tune and installed that but it had no effect.

I got sick of it and returned the tune to stock and put some stock (NOT stage 2) injectors in that I had laying on a shelf. I have s2 sensors and AGP WGA so I couldn't drive it around. But I started it and it was running worse than ever. So I reset the PCM (disconnected the battery) and started it up. It struggled for second as would be expected for not having any trims or anything stored. Then it ran fine. I logged it for 5 mins or so and not a single misfire. I went back inside and came back out later and started it up. It started to surge so I tapped the throttle and it quit immediately. Probably because it's freezing outside. I logged 18 minutes idling without a single misfire, not one... I was in the 20s+ in mere minutes with the 1300CC injectors in. I did notice my vacuum is @ around -16 vs the -18 that it usually is but again it's freezing outside and I assume that it's effected by the cold.

I am getting worried that my tuner doesn't know what to do. I am also starting to think that the injectors are junk. But I don't want to freak out or piss off my tuner either.

Thoughts?
Thanks in advance.
 
See less See more
#5 ·
The injectors are FID.
I have a trinity that I am using the load the tunes.
I bought a Stage 3 Turbo, that's why I bought the bigger injectors. (Room to grow) The Stage 3 turbo however, won't be here for around 6-8 weeks and I cannot be down that long. So I will have to tune it now and buy a couple more tunes later when/IF I get the stage 3 setup.

To answer some other questions.
I bought a boomba fuel rail because it has a FPG built onto it. I almost stripped out the passenger side rail bolt because the stock ones aren't long enough. So no FPG for now.
I have not yet tried replacing the upstream o2 sensor. I will look into that.


What I have learned.

My battery was starting to fail so I replaced that.
I had a boost leak at the rice plate so I fixed that.
I am currently around -14 pressure / vac. Used to be @ 18-19.

After all that, after clearing all the fuel curves and what not. I drove it around and the misfiring started again. It's bad. But again, with stock injectors on it I don't get any of that..

I will try some of these ideas.

Thanks,
TCD
 
#3 ·
first invest in a aem ugo wide band.. you need to figure out what the air fuel ratio is ...

go to autozone and borrow (lone a tool ) a fuel pressure gauge.. it has a long hose and you can tape it to the windshield and drive around (pull to) and make sure it stays at 58psi

try pulling the fuel rail , energizing fuel system and the apply 12v to each injector for a couple of seconds... make sure there is a good mist, not a stream (youtube has a few examples)

if all that is good.. i'd try replacing the upstream o2 sensor, again autozone --- don't strip it.. get this http://www.autozone.com/images/MEDIA_ProductCatalog/m3490183_prd-Oxyge- Sensor-Socket.jpg the sockets suck.

you'll need a tune from someone who's accustom to srt's (free plug for duster360) who did the tune?
 
  • Like
Reactions: HybridKid
#4 ·
Yeah these cars are haunted when it comes to injectors, fuel pressure and ignition. I would use a 9v battery to activate the injectors if you do the test the fixit said.
I recently went street tuning on some brand new 1650cc injectors, now keep in mind I run a standalone and was upgrading to newer High impedance injectors from Low impedance 1600cc injectors. The tuner ended up having to add 20-40% more fuel in parts of the VE/Fuel MAP table to get it to run at 14.0 and not go lean at TIP in. Fuel pressure was good and the other weird thing is that at 11 PSI the data log was showing 69% Duty Cycle on the injectors. Then I go to drive it around the block this past Sunday and at cruising AFR was 10-11 @ 2500 RPM. During the tuning session it was 14. I tell you this/these cars are haunted or something some times.
 
#6 ·
I have not yet tried an O2 sensor but here is what I have tried.

I got another set of Stage 2 injectors and after some haggle I installed them w/ the boomba fuel rail that contains a fuel pressure gauge. The fuel pressure is cruising along at a steady 61 PSI at idle.

Once installed, I reset the PCM back to stock and then applied the rescale for the stage 2 injectors. I then reset the PCM (batt disconnect) and started the car.

Smooth as a baby's bottom for about the first 10'ish minutes. Then an onset of random pops in the exhaust. They did not feel as harsh as the misfires experience with the 1300CC injectors but I could hear them. They also do not register on the trinity as a misfires at all. Seemed like no matter how many I experienced, I would get no misfire counts on my trinity. While doing this, I realized that my car sounded like a diesel. I mean it's suddenly LOUD. Oddly I can't really hear much of it when I open the car door. Only when the door is closed do I hear this horrible sound and it follows the RPM of the engine. It also only seems to set in after the engine is warm and get quieter the higher the RPMS.
After some reading I am worried about oil pressure and plan to install the oil pressure gauge tomorrow. I am also concerned that the timing belt tensioner could cause this noise. It's hard to hear in the video I posted below. But that "running water in pipes" sound is what I am hearing from the front of the motor as well. It's new, I had not ever heard this until recently.


Strange sound from around the front cover. ^^

I recorded this tonight while I held the throttle at 2000 RPM and then let it down to around 1500 RPM. If you listen very closely you will hear the "pops". My car was never "perfect" but it was also never anywhere close to this bad.


Random pops/misfires.


A thing to keep in mind is that it seems that if I reset the PCM it runs fine for around 10 mins and then starts acting dumb.


Could plug gap be causing this at idle? What should the gap be? I have read many different articles and I think I set it @ 0.35.

Thanks in advance.
 
#8 ·
So I am starting to get a little panicky. :/

I cannot track down this issue, and it's really starting to chap my a**.
I have installed / replaced the following through all this.. Some just because I had it one hand and wanted to get it done.

* New battery
* New MFS switch connector + relay mod.
* New Headlight connections + pin mod + conductive grease mod.
* New cam position sensor + magnet
* New NGK 4306 Copper plugs
* New Granatelli Spark Plug Wires
* New Mopar coil pack
* New Mopar oil pressure switch
* New gauges
* Oil pressure
* Wideband
* New 1300 CC injectors (Makes the problem much much worse)
* Used boomba fuel rail w/ pressure gauge

I was finally able to create a video that actually captured the popping that I am hearing.



The pops in this short trimmed clip can be heard at 12,16,21 and 23 seconds.. These are mild compared to the some of the ones that I have heard but can all be felt firmly on the floor board.

What I have not done yet, that I am considering doing.. Is replacing the intake manifold gasket. I think there is a small chance that the intake mani is leaking under vacuum but not under boost when I test for leaks. Replacing the fuel filter and checking the host under the mani again..

Thoughts?

I am getting desperate here..

:crying:
 
#9 ·
could be a vac leak, make sure to torque and blue loctite .. you can test it by spraying around the gasket with brake cleaner -- and listen for the idle change..

mine popped on the bottom near the thermostat housing..

then, i'd do the upstream o2
 
#10 ·
What is your AFRs like while this is happening?
This is at idle and cruising, right?
Did a boost/vacuum leak test?
Just wondering if it is not a leak, it sounds like there is too much fuel in the exhaust system that is lighting off as the car runs longer. The catalytic is probably providing the ignition. Wonder if it is clogged??
 
#11 ·
Great questions.

So the video I posted was in my garage around 2500 RPMS.. On the highway, at cruising speed however, the pops tend to be much louder.

I don't have a video or reading of my AFRs at cruising speed or elevated RPMs because I just got my AFR bung installed and haven't fully / perm wired my gauges in yet. (Glowshift gauge) GlowShift Black 7 Series Digital Wideband Air/Fuel Gauge )

I do have an idle AFR reading..


14.6-14.7

I did do a boost leak test and didn't detect anything until I got to ~30 PSI. I need to check again but I think I closed that leak. The problem persists.

There is no cat, straight 3" pipes all the way back the 02 housing back.
It's probably important to note that this is a stock PCM with a stage 2 rescale form duster. Not sure if that's going to affect things or not in terms of how the AFR and fuel should behave.


Thanks in advance,
TCD
 
#12 ·
14.6-14.7 is appropriate at idle.
The cam sensor and magnet are MOPAR?
Still getting the misfire code or any code?
I don't know how this part of the DSP works but have this question.
You still using both OEM O2 sensors?
Have you tried using one of those code eliminator fitting on the 2nd O2 if you aren't already?
 
#14 ·
The cam and magnet are Mopar.
The Coil pack is Mopar. The only reason the wires aren't mopar is because Modern auto doesn't sell them anymore. That said. The problem has remained the same through swapping all of those things.

It does not set the misfire code on stock Mopar Stage 2 injectors nor do the misfire counts move. At most I usually end up with 1 misfire on a couple of cylinders when running the Stage 2 injectors. Which is what I have in there at present.

When I put the 1300CC injectors in the car it missed like crazy and throws a CEL shortly after. Usually within the hour sometimes way sooner. The 1300CC injectors also throw the misfire counts up super high on the PCM whereas the Stage 2 injectors do not.

The o2 sensor in the o2 housing is OE as far as I know. I have not replaced it yet and I doubt the PO ever had a reason to. I will have to pull it and look.

The rear o2 sensor has the non-fouler mod and has worked great for around 30k miles. Throws a CEL light in minutes without it. My understanding is also that the rear o2 does nothing in terms of fuel trims etc. That the ECM alerts if certain values aren't met.

The other thing to note is that when I pulled the down pipe off the o2 housing to install the bung for the AFR. The pipes were black as expected but very clean in terms of any sort of build up. Looks like the car has been running well for some time.

The TPS and IAC wiring looks a little weathered. However, I can shake the sh** out of them and nothing changes.

I am getting ready to order the IAC rewire kit (already have the TPS) and a DCR fuel filter today. Does anyone have any experience with DCR fuel filters? Am I wasting my time/money not just finding a Mopar?

Thanks in advance,
TCD
 
#15 ·
You're correct tho I think.. I don't recall every getting any of these backfires when in boost. But it's a little harder to tell when you're focused on waxing the mustang next to you.

I have a replacement set of 1300CC injectors that were sent to me by FID. I have not had a change to try and install them yet. I want to solve this issue with the stage 2 injectors in it before I go back to them.

I have sprayed brake parts cleaner around the intake but admit that I was not able to get it around the bottom very where. I will be more pointed about getting all the way around the intake tonight when I get a reading of the AFR at 2500 RPMS.

I did leak test/boost leak test them and they did not leak. They even send me 15mm orings to make damn sure.


Thanks in advance,
TCD
 
#16 · (Edited)
Check the cam sensor wiring, even though it is not throwing a code it may not be a large succession of consecutive errors to throw the code.
I would do the same, fix the issue with the Stage 2 injectors before going to the 1300s.
With that said it seems like the extra fuel from the 1300s creates more of the problem. Maybe because of the extra fuel.
Ok, so below is what we know has to happen (everything else being perfect) when you change injectors and in your case IIRC the Stage 2 were not native to this car or the PCM either.
  • The PCM has to be rescaled to match the injector size and latency.

So at which point in the beginning was this all perfect without the misses and pops?
Not racing/wot, partial boost is good enough to check if this happens only in vacuum.:wink:
Just checking everything here but are the OEM O2 sensors in their correct locations?
 
#19 ·


That is a video of wideband activity under throttle.

I will check the cam sensor wiring. I forgot to this time..
The PCM was rescaled for the stage 2 injectors.
The PCM was in the process of being tuned for the 1300CC injectors but I had to back off that and reload the s2 rescale.

So this was all perfect with out the pops for a long time. I noticed a loud POP one night on the way home and blew it off as a one off. Then I started to notice them a little more but again blew it off because they were so far and few between. One day, without noticing anything odd it threw a CEL. The code was a misfire on cylinder 4. After replacing the CP, wires, plugs and still getting the CEL. I swapped injectors 3 & 4 and watched the misfire counts on my trinity. The problem followed. So I ordered new injectors and 2 tunes. The new injectors went crazy and were misfiring all over the place. So I bought another set of stage 2s and slapped them in and put dusters rescale back on. No misfires but these pops that are getting more and more frequent.
What do you mean by OEM o2s in their correct locations? There is only the one in the o2 housing and the one behind where the cat is supposed to be. Right?

Thanks in advance,
TCD
 
#18 ·
Sounds like you're on your way to troubleshooting and likely fueling related or ignition. If you could data log the computer over the OBD-II port and and watch what a wideband is doing it might speed troubleshooting. At first with describing running problems with both the large aftermarket and then Mopar Stage 2 injectors and running normally or near normal when putting back to stock (or even running S2 injectors on a stock tune, which will work since fuel trims can compensate for most the difference), I'd suspect something in the tune but you're working with a reputable tuner. What does he say and did you get the injectors from him or buy separate and have him make a tune?

Since you've already dumped a lot of money and are working on the fueling PCM control and sensors, vacuum harness, etc. I might suggest one thing to rule out i the ignition system. I've have some old post about them but I was never a fan of the Granatelli wires to put i mildly. Unless they're making conventional wires now, their solid conductor core wires shouldn't be used on modern computer-controller applications due to electrical and radio frequency interference (RFI/EFI) they can generate. I've also heard of a few failures over the years but that goes for about any wire. Just to rule out or at least exclude as much as possible you don't have an intermittent ignition problem you could pick up a set of regular auto part store plug wires and use some dielectric grease in the boots. And ignition problem would most likely appear under high load, high boost but it's fairly cheap to rule out (and I'd personally run regular auto part store wires over Granatelli anyway if you can find a set with good insulation).
 
#22 ·
I have to build the cable to connect the wideband to the trinity. Then I will be able to capture that information + regular information.

I got the injectors as a package deal. Now that the problem has mildly spread to the stock injectors as anyone would he is defaulting to my car has a problem. Which now, I think it does.

I have no issues putting some cheap autozone wires on to see if it changes anything. I have some I used to get me by once that I can slap on there. My confidence is high however that this will not change anything as the problem has been pretty consistent through it all.

I am starting to think I have a head / valve seal problem. Seems like a valve is intermittently not sealing maybe? I need to find a borescope that can fit in there and look around well.

I just can't ever win.. :/

Thanks,
TCD
 
#21 ·
Couple of thoughts after watching the video. Not sure if this is a problem but wanted to voice it out loud.
The AFR sure likes to stay around 14 when you apply throttle, one would think the "TIP" in would go slightly rich and once the RPM stabilize settle back down into the 14s.
It seems to me also when the pops happen the AFR seems to jump into the 15s. If the misfire is due to a cylinder or two not firing, shouldn't it go rich instead of lean?
 
#24 ·
I don't recall what happens with the stock computer and what it uses as it 'relearns' after a reset. Not sure if it goes into a Closed loop versus Open loop mode. 10-20 minutes though is an average time most ECUs use as it warms up, so it is usually Open Loop (not using the O2). After the engine is warmed up it starts using the O2s as reference and a different table.
Try resetting the computer after the engine is warm and see if it still happens. The thing is though you may still be in that 'learning' timeframe for the PCM but it is worth a try.
An exhaust leak before the O2 sensors or really close could cause this more than a valve leaking. Have you done a compression and leakdown tests?
IIRC a member recently posted he had a crack in his exhaust manifold that was causing some problems, don't remember what but see if you can find his thread.
Maybe Blackbird can clarify and correct some of my ramblings.;)
 
#26 ·
Well.. I warmed it up and reset the PCM. Hooked the battery back up after around 15 mins.. The popping / misfires were immediate. So I had debunked that the PCM reset affects anything.

I have not done a compression test yet because the my tester was filled with 2 stroke oil late this summer. I will get it back out and see if I am able to blow that out. If not I will buy a new one and test.

I did do some boost leak testing.. I was getting a leak somewhere ~30 PSI. I am not 100% sure if I got it because both of my boost leak testers suck. Could have been the boost leak tester leaking at that point. The funny thing about that is.. I did track one down to the rice plate. Maybe it wasn't the rice plate? I will try and find a way to make those PsOF to work long enough to test it again. Before any of this i had made the statement that I was starting to suspect my mani was cracked. I didn't think that would cause any of this tho.
This may sound silly to come.. But I used a mechanic's stethoscope to listen to the injectors and motor. I have high confidence that the injectors are hitting very consistently and I am not hearing anything unexpected from the head area.

I think I am going to replace the o2 sensor in the o2 housing for shits and giggles. What brand should I get?

I did order:

A borescope that should fit into the spark plug holes nicely and provide good video of the top of the piston and hopefully the valves if I can get it to bend / flip while it's in there.

A DCR fuel filter / (I assume) pressure reg

Thanks,
TCD
 
#31 · (Edited)
So... I got my trinity logging my AFR through analog input 2. Seems pretty accurate.

So how do I log so that others can review my logs and give their input?

Do I log straight to the laptop? Does that capture more information than a trinity log? If I have time I plan to do another boost leak test up to ~30 PSI. If I have to make a new tester with ports on the side of the PVC pipe I will.

Ordered an "NTK 23159 Oxygen O2 Sensor Genuine Direct Fit ng". No one has it locally..
Thanks in advance,
TCD
 
#32 · (Edited)
I am still trying to figure out if logging with a laptop through a trinity will provide more information than just a trinity log.. Anyone?

In mean the time I got out my compression tester and ran a compression test.

1 : 152 ( https://youtu.be/4Qkgzm7qMW4 )
2 : 152 ( https://youtu.be/UkljOXWccX0 )
3 : 152 ( https://youtu.be/QDWsIoFDyH8 )
4 : 152 ( https://youtu.be/MvcmD0dWh7A )

This was a cold compression test. I just read that it should be up to operating temp. I am not removing my plugs @ operating temp.

I know, incredibly consistent but that's why I did it all over again with video evidence in case I am somehow doing it wrong. Needless to say my worries about a head problem have gone down significantly.

I am still waiting for my NTK o2 sensor to get here so I can change that and I have a boost leak test I am going to try and do again tomorrow.

Thanks in advance,
TCD
 
#33 ·
After doing some thinking.. I see how doing a operating temp pressure test could have relevance so I am going to do one. I don't like to pull the plugs out of aluminum heads when they are hot but I guess I will take my chances and do it anyway. With numbers so consistent I can't imagine the outcome being much different.

Thanks,
TCD
 
#34 ·
Warned the engine up till the ECT it 200 and then went back down. Performed compression test.

1: 150
2: 151
3: 150
4: 150

This makes me even more comfortable that the head is operational and not malfunctioning. This doesn't eliminate an intermittent sticky valve but I am definitely not leaning towards a head issue anymore.

I change the fuel filter with the DCR fuel filter that I had ordered. Nothing changed in regard to the pops in the exhaust. However, for around 5 mins or so. The FP gauge on the boomba fuel rail wasn't bouncing around much if at all. I was starting to think that this would be permanent but it didn't take long for start bouncing around like it was before and others have stated that this is normal for a non-return type fuel system. The old fuel filter didn't seem to be too challenged in resistance when I blew through it but I did get a tiny bit of back pressure whereas the DCR has zero resistance.

I have attached a log file of my car running for around 15 minutes. This is a log form the trinity so it may be missing things that one would need / expect when looking at these issues. I also think I am seeing a trend towards leaning out when these pops are happening. If you want to use the log you will have to change the extension from .txt to log.

One last note.. When holding the accelerating pedal at an elevated RPM. I swear I am starting to hear a high pitched squeal in the background but it's nearly impossible to tell what it is or where it's coming from. Could just be something on the accessory side of the engine..

Thanks,
TCD
 

Attachments

#36 ·
The electrodes are bright white, they look great. The ground straps have a very very light whitish color to them that I can wipe off with little to no effort. I posted pictures on a facebook and several people told me I worried to much. If anything they look like the car may be running a touch lean. They are also very consistent from plug to plug..

Shook the shit out of every connector I could find under the hood and didn't get much if any reaction from the engine. When I was looking at that log data the o2 sensor (raw) seemed to be pretty unstable. That could be normal tho I can't be sure. I can't wait for the NTK o2 sensor to get here.

I am also rebuilding my boost leak tester. When I get a couple more fittings I will be able to hook it to the air compressor and control the pressure from the regulator I just bought rather than filling it to pressure and then running around looking for leaks and then filling it with pressure again when it runs out.

Thanks,
TCD
 
#39 · (Edited)
I replaced the two piece hose that goes from the bottom of the intake to the brake booster with a single host the sized for the brake booster side.. I will never understand why dodge decided to do what they did there. I also lightly clamped the end at the brake booster and mildly clamped the end on the intake. That was a big fat random boost leak where the two pieces of hose were tied together with the plastic fitting.

I then replaced the host that went from the TB to the 2 way check valve and lightly camped that as well. I then removed the check valve I bought from modern auto and restored it back to the plain PCV and tightened that down. I was leaking boost there as well.

So I did another boost leak test and this time ~32 psi was the max it reached. I have quite a bit of leaking around my solenoids now but have been told there isn't anything I can do about that. I have always had that too so I don't think that's it. I do however hear something else leaking..

So I listened around and tracked it to the TB area.. I spray like crazy but don't pick up on any changes so I start reaching around it. On the backside, there is loose spring and when I start touching around in that area the sound lightly changes. Could it really be that my TB is leaking vacuum and causing these pops? I am also down even more vacuum now too. Somewhere between -12 PSI to -14 PSI. I imagine moving the solenoids around so much is why my vacuum is down.

I am also still getting the pops at cold startup or warm, doesn't matter.

/me cries.:mopar:
 
#41 ·
Agreed. Your vacuum is is suspiciously low. You should be pulling ~ -20 in/Hg at warm idle (unless you live in Denver).

If you can find no leaks, double check your cam timing.
Personally to me it still sounds electrical. For instance, erroneous signals are telling the PCM to fire a spark when it's not supposed to.
 
#43 ·
Yes the battery was disconnected during all the boost leak testing so in essence is was disconnected for days as I worked out the hose issues.

I came home tonight and swapped out the upstream o2 sensor. Made zero difference. I really didn't expect it to but I had already bought it so what the hell.

Hooked it back up to the boost leak tester. There is still a hiss coming from somewhere near the TB. On the back side of the TB there a spring that I think belongs to the throttle. I swear I saw bubbling coming from this area but before I could get a camera on it, it stopped and of course I can't reproduce the issue. But I still hear the hiss.

I started the car and had my son record the vacuum/boost gauge while I toyed around with various vacuum lines. It never bounced much. It did not like it when I started really messing with the TIP sensor but I think that's expected considering what I was doing.

I think I am done. It refuses to run correctly and is causing me major problems both financially and anxiety wise as I need a car that runs most of the time, Not one that is down for months at a time. Not to mention it's eating away at precious time I should be spending with my kids.

I am going to miss it I am sure but there will likely be a part out on FB or CL soon. I won't get anywhere near what I have in it in new parts alone even with a part out. I might take a few 9th inning cracks at it but I doubt it.

Thanks for all the help.

TCD

:crying2:
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top