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Is my Trilogy FPR bad?


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#21 techboy

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Posted 08 September 2019 - 09:03 PM

My new spark plugs showed up on Friday.  So on Saturday I spent some time swapping plugs and doing a compression test along that way.  I may have discovered why the car has been running not so "great" this whole time.  My compression test yielded 100 psi compression across all 4 cylinders.  The FSM calls for a 142 and a minimum of 113.  Ironically, I've been emailing Randy (Dad) the past few weeks about getting a new short block built for this winter anyway.  I've never had a good feeling about this motor.  Some of you that have been around for a long time may remember when I built this motor I had no oil pressure at initial startup, which I got corrected, but it still happened.  And then, 2 years ago, I had a low oil pressure issue again and had to replace the oil pump.  So, I highly suspect damage has been done to this motor.

Anyway, I replaced the plugs, and upped the FPR to about 42/43lb range.  I took the car out for a test drive and it actually ran pretty good.  I also checked the CTS since the car was warm and it read 474 ohms.  So, I'm pretty sure the the CTS is fine.  I think the car is rich because there is just not enough compression to burn all the fuel.  I took the car out again tonight to show and it ran well.  So, I've at least bought myself some time till I figure out what I want to do this winter.

Edited by techboy, 09 September 2019 - 10:03 AM.

1988 Starion ESi-R ... crushed by a tree 10/31/11 - back from the dead 8/2016
1988 Conquest TSi ... current driver - sold to Bigjoe 6/2016
1987 Conquest Flatty ... F/S thread - sold 8/2014
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1999 Eclipse 4G63 ... heavily modified.
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#22 Preludedude

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Posted 08 September 2019 - 09:10 PM

Well good.   Go ahead and start planning a build, and still be able to enjoy driving the car.  

That's a great scenario.   Not many of us have/had that luxury. :)

#23 BC_99

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Posted 08 September 2019 - 09:40 PM

Was the compression test done on the engine after warmed up to operating temp, or cold engine?

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#24 rcm

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Posted 08 September 2019 - 09:44 PM

I ran those injectors at 38 psi with stock fpr.But as you found out it does better at 42psi and up because it atomize the fuel in a better cone shape mist.Make sure your in tank and inline filters are good.

#25 croquest87

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Posted 09 September 2019 - 03:32 AM

Perhaps double check your compression w different  gage and do leak down test.Just to make sure. I had a cheap compression tester throw the reading off before.Also injectors disconnected and wide open throttle. Check it warm and cold.  Little bid of time that's all before you venture into building the motor.

Gage w built in check valve could give you better results but if that also shows at around 100ish or less? Its time for rebuild.

FYI  after l rebuilt my motor reading was 142ish after 100 miles of break in. 145-147 after 3500 miles once things settled in. Oil pressure 27 psi balance shafts removed and mechanical head set up.

Edited by croquest87, 09 September 2019 - 03:44 AM.


#26 Turbo Cary

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Posted 09 September 2019 - 04:07 AM

Maybe the cam jumped time? If all 4 are low I would double check timing.

#27 Jay40245

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Posted 09 September 2019 - 06:08 AM

I've only skimmed the responses, so someone may have already suggested this. If so, I apologize. I was suspecting that I had a faulty trilogy fuel pressure regulator as well. To monitor fuel pressure while under boost, I installed an electronic fuel pressure gauge to verify that the regulator was doing its job (1lb increase per lb of boost). I believe I purchased it from motocam 360. It's the one that screws into the back of the top hat with an adapter. Good luck with  your problem.

#28 techboy

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Posted 09 September 2019 - 10:00 AM

View PostBC_99, on 08 September 2019 - 09:40 PM, said:

Was the compression test done on the engine after warmed up to operating temp, or cold engine?

BC

Engine was completely cold.  All I did was start it and back it out of the garage.  It was such a nice day I decided to work outside instead of in the garage. So I moved it about 15 feet.

View Postcroquest87, on 09 September 2019 - 03:32 AM, said:

Perhaps double check your compression w different  gage and do leak down test.Just to make sure. I had a cheap compression tester throw the reading off before.Also injectors disconnected and wide open throttle. Check it warm and cold.  Little bid of time that's all before you venture into building the motor.

Gage w built in check valve could give you better results but if that also shows at around 100ish or less? Its time for rebuild.

FYI  after l rebuilt my motor reading was 142ish after 100 miles of break in. 145-147 after 3500 miles once things settled in. Oil pressure 27 psi balance shafts removed and mechanical head set up.

It is a cheap compression tester.  It's the one they have at Harbor Freight.  I've had it for a number of years.  I think I leant it to tsi_tom at one point.

View PostTurbo Cary, on 09 September 2019 - 04:07 AM, said:

Maybe the cam jumped time? If all 4 are low I would double check timing.

That's not a bad idea, That thought hadn't crossed my mind.

If I decide to build another motor, I won't be a huge deal.  I have a spare good block I've had for years ready to do.  I can it all built and then just swap motors.  We'll see.  Right now, the car is running much better.  It ran real nice coming home from the local cruise and pulled nice boost till about 80mph then I let off.  Didn't wanna get pulled over.
1988 Starion ESi-R ... crushed by a tree 10/31/11 - back from the dead 8/2016
1988 Conquest TSi ... current driver - sold to Bigjoe 6/2016
1987 Conquest Flatty ... F/S thread - sold 8/2014
1987 Conquest TSi ... parts car - sold to Coldscrip 12/2011
1999 Eclipse 4G63 ... heavily modified.
Feeback Thread | Motor rebuild thread | Restoration thread

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#29 tsi_tom

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Posted 09 September 2019 - 10:03 AM

When I used that compression tester it was fine. I thought mine was 132 lbs.
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#30 ucw458

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Posted 09 September 2019 - 02:23 PM

Try a different compression tester.  And do it with the engine warm.  Warm engines give higher readings.  Cheap testers can give false low readings.  I have a cheap one that reads at minimum 50 psi lower than my good one.



Losing oil pressure momentarily wont kill rings and cause low compression.  What it can do is damage bearings if run too long.  But you would have heard knocking or had engine failure by now if you had damaged them.  Your engine may be fine.



As for running rich, low compression doesn't normally cause that.  The numbers have to be really low for that to happen.  I've heard of SQs with 90 psi compression that were still running good just low on power.  SQs do run slightly rich from the factory.  Also aftermarket injectors can make them run rich.  Some injectors react faster than others and that can change your fuel ratio.  Aftermarket injectors aren't the best replacements.  But stock replacements are getting scarce.  So you may have to live with slight issues that aftermarket injectors can cause.
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#31 BC_99

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Posted 09 September 2019 - 05:02 PM

View Posttechboy, on 09 September 2019 - 10:00 AM, said:



Engine was completely cold.  All I did was start it and back it out of the garage.  It was such a nice day I decided to work outside instead of in the garage. So I moved it about 15 feet.

Recheck it at operating temperature. Expansion and contraction. When warm, the metal rings, pistons, etc all expand a little and the tolerances close up. I bet your readings are showing low from that and possibly a faulty or less accurate gauge. It sounds like the higher fuel psi and new plugs helped it, snd it's pulling good with no visible smoke etc? I believe that the engine is probably just fine.

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#32 techboy

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Posted 09 September 2019 - 08:58 PM

View Postucw458, on 09 September 2019 - 02:23 PM, said:

Try a different compression tester.  And do it with the engine warm.  Warm engines give higher readings.  Cheap testers can give false low readings.  I have a cheap one that reads at minimum 50 psi lower than my good one.

Losing oil pressure momentarily wont kill rings and cause low compression.  What it can do is damage bearings if run too long.  But you would have heard knocking or had engine failure by now if you had damaged them.  Your engine may be fine.



As for running rich, low compression doesn't normally cause that.  The numbers have to be really low for that to happen.  I've heard of SQs with 90 psi compression that were still running good just low on power.  SQs do run slightly rich from the factory.  Also aftermarket injectors can make them run rich.  Some injectors react faster than others and that can change your fuel ratio.  Aftermarket injectors aren't the best replacements.  But stock replacements are getting scarce.  So you may have to live with slight issues that aftermarket injectors can cause.

View PostBC_99, on 09 September 2019 - 05:02 PM, said:

Recheck it at operating temperature. Expansion and contraction. When warm, the metal rings, pistons, etc all expand a little and the tolerances close up. I bet your readings are showing low from that and possibly a faulty or less accurate gauge. It sounds like the higher fuel psi and new plugs helped it, snd it's pulling good with no visible smoke etc? I believe that the engine is probably just fine.

BC

Thanks for the replies gentleman.  I definitely have access to a different compression tester from a professional shop - should be a Snap-On one.  I will get my hands on that and I will retest with a warm engine this time around.

Car doesn't smoke at it all, under normal acceleration or boost, and it never has.

I think when you restore to this degree you just get paranoid about everything that doesn't seem quite right.  :wacko:
1988 Starion ESi-R ... crushed by a tree 10/31/11 - back from the dead 8/2016
1988 Conquest TSi ... current driver - sold to Bigjoe 6/2016
1987 Conquest Flatty ... F/S thread - sold 8/2014
1987 Conquest TSi ... parts car - sold to Coldscrip 12/2011
1999 Eclipse 4G63 ... heavily modified.
Feeback Thread | Motor rebuild thread | Restoration thread

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