2003 srt-4 compression test results - Dodge SRT Forum
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post #1 of 10 (permalink) Old 01-24-2019, 12:07 PM Thread Starter
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2003 srt-4 compression test results

So did a compression test on this old motor and as it turns out seems healthy.

besides fouled spark plugs and what appears to be to much fuel or water on them not to sure.

cylinder 1 cylinder 2 cylinder 3 cylinder 4

165-170 160 150 160


only thing is that while doing this the battery crapped out so i had it on jumper cables .

i swear it cranked slow and took about more then what seemed like forever to get the compression numbers.
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post #2 of 10 (permalink) Old 01-24-2019, 12:21 PM
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ok... so whats the problem?

those numbers look good to me.
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post #3 of 10 (permalink) Old 01-24-2019, 01:48 PM Thread Starter
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No problem just , wanted some input, out of all these years on this forum theirs so many people who argue the numbers. some say anything over 100psi is good others say elevation matters and that it should be around 170 psi.

but the numbers don't like compression good.

this is more of a log for me honestly , i wanna build this car so it drives good. before i decide to rebuild it and big turbo it.
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post #4 of 10 (permalink) Old 01-24-2019, 02:48 PM
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U need to get and FSM

You probably should get a Factory Service Manual rather than solely rely on posted information here on this forum.
That document was written by engineers. Posts here may not have been.

FSM page 9-104 has a chart for the 2.4L DOHC engine which shows:

Compression
Pressure
1172-1551 kPa 170-225 psi

FSM page 9-26 also says:
The recommended compression
pressures are to be used only as a
guide to diagnosing engine problems. An engine
should not be disassembled to determine the
cause of low compression unless some malfunction
is present.
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post #5 of 10 (permalink) Old 01-24-2019, 02:53 PM
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U need to get and FSM

duplicate.
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post #6 of 10 (permalink) Old 01-24-2019, 09:43 PM
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rule of thumb for me is 10% difference... i wouldn't do nothing to that motor but turn her up lol
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post #7 of 10 (permalink) Old 01-24-2019, 10:24 PM
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As long as you were cranking with the throttle fully open and the ignition disconnected (which should engage the WOT fuel shut-off during cranking) and doing the compression test preferably with a warm engine, you should get accurate results. Even on a cold engine those numbers look fine.

How many miles are on the engine and what are your plans? If you're getting ready for a big turbo upgrade or plan to run nitrous and trying to evaluate engine health, you could also consider a cylinder leak-down test to see how well the piston rings are sealing, but with those compression test results being fairly healthy I won't bother unless you suspect other problems.

A few other things you could do would be to send an oil sample in for analysis at a reputable testing lab which is one of the best ways to check for premature bearing and internal wear without taking the engine apart. You could also use a bore scope down the spark plug holes to check the cylinder walls and piston crown (top) for signs of wear and damage, but again I likely wouldn't be too worried with a healthy compression test result. Last, besides the piston rings and bearing wear, if the engine has a lot of hard miles or is getting up there above the 100k mile range, the plastic guides used to keep tension on the chain that drives the balance shaft assembly might be worn and allowing excessive chain movement.

There's a potential they could break and take out the lower end of the engine at worst and if they're rattling around might cause noise the knock sensor interprets as detonation which could cause the computer to run less spark. If you're looking to do a budget build you could always consider dropping the pan, taking a look for signs of metal debris, check the balance shaft chain tension, and if the guides are still in decent shape tighten them to specification or cut the chain and preferably plug the oil feed passage (you'd want to leave the assembly in place to help control oil movement unless you install a good baffle/windage tray).
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post #8 of 10 (permalink) Old 01-24-2019, 11:25 PM Thread Starter
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I do have a owners manual. Ill check it out. Figured the internet was a trust with place lol jk.

I have a ton of work to do to this car.

Heater core issues, removing selnoid packs, rewire tps, fix the cracked turbo manifold . Then once I get my CDL and start rolling in the dough I plan on building it.

Don't wanna get ahead of my self like can change at any given moment. So I live my life a quarter mile at a time.

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post #9 of 10 (permalink) Old 01-25-2019, 11:06 AM
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Quote:
Originally Posted by Yellowneon View Post
I do have a owners manual. Ill check it out. Figured the internet was a trust with place lol jk.

I have a ton of work to do to this car.

Heater core issues, removing solenoid packs, rewire tps, fix the cracked turbo manifold . Then once I get my CDL and start rolling in the dough I plan on building it.

Don't wanna get ahead of my self like can change at any given moment. So I live my life a quarter mile at a time.
I believe someone on here (???) has posted links to the Field Service Manual (FSM) aka "Shop Manual" aka "Service Manual".
But I don't remember exactly where it is.
The FSM is much more comprehensive than the Owners Manual of which you speak.
Sounds like you will need the FSM since you will be doing a ton of work.

Heater core will be a bitch by some accounts here.

I personally would advise against removing the solenoid packs on top of the air box.
The PCM uses these to manage/optimise the power of the motor in varying environmental conditions.
Meaning you could end up making less power and have less drivability since the PCM won't be able to well-manage your motor.

TPS is an easy fix. Modern Performance has the repair kits:
Mopar TPS Wiring & Connector Repair Kit, Throttle Body & Intake Manifold: Store Name
or you can get a kit at your local Dodge dealer if you prefer.

Small cracks in the turbofold are inevitable and normal.
Giant crack are a problem though.
I've heard it is possible to fix crack by brazing.
I've not found it necessary to touch my S3 turbofold since it was installed in 2004.
I'll bet it has cracks but boost still spikes to 21PSI and holds 17PSI even after all these years of beating on it.
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Last edited by Simon.Starkie; 01-25-2019 at 11:12 AM.
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post #10 of 10 (permalink) Old 01-31-2019, 03:25 PM Thread Starter
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Simon.Starkie - Issue is i pulled off the exhaust manifold and it had multiple cracks inside by the flap. and im scrap it and do an ebay build just for fun, to get the car rolling . then save up for a decent turbo kit or a used one. As for the solenoid pack it will stay just two of the plugs will be unplugged and have a resistor is them to fool the computer. ive had 4 srt-4 or 5 lol lost count i have done it two 2 of them no issues, and honestly runs better as weird as it sounds.
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