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1G Car surging, poor gas mileage, ect

Batmobile

Proven Member
431
1
Feb 23, 2004
Olathe, Kansas
I own a '92 Plymouth Laser RS awd. Engine rebuilt only thing additonally down was the balance shaft removal kit and put my 3s TT fuel pump in. Everything else is stock.
My first issue I had with the car after getting the motor back in was 1/4 cylinder was not firing. I replaced the ptu after doing the manual diagnotic check on it. That didn't solve the problem. Finaly found someone willing to let me use there ecu, and it fixed the problem.

Now I bought a remaned ecu from O'reilys. The stickers on case have been removed for rebuilding purposes Im assuming? What Im leading to with this is I'm not 100% positive its the right ecu for my car. The #'s on the white connector is 6578m


Now to my acutally problem on hand now that I have explained things I have already replaced.

I filled up my tank after I did a test drive with the new remanned ecu in car. I got 96 miles on that 14 gallons I put in. Now about 4 hours of that is all idle time trying to figure out the surging and rough running issues. IE boost leak checks, purging injectors which all injectors made a differnce in motor, reading logger while idling, O-rings on TB It completly ran out of gas. I had to put gas init in my driveway.

Ive read at many serniors of what the surging is. Only thing I have not yet done is removal of the "wax pellet" spring in the TB.

What more info can I add to help you guys HELP me figure my problem out?
Its driving me insane. Also additional info fuel tank has also been replaced and flushed out along with new lines to fuel filter.

Car is running extermely rich. I replaced the black plugs with new ones and they where black with in 5 minutes.
What Im I missing?

Thanks in advance.:cry:
 

drooseph

Proven Member
168
0
Nov 4, 2010
san diego, California
For clarification, you put a higher flow pump with no adjustment of fuel pressure or fuel tuning of any kind. If your running higher than stock pressure untuned its probably running super rich.
 

gofer

Moderator
8,148
1,385
Feb 18, 2006
South Gilbert, Arizona
The stock 3/S pump (if its turbo) flows a mere 180lph @ 43.5psi (so even less on your Laser), nothing that the stock fpr couldn't handle if its a working unit. You mentioned a logger so I'm assuming that you've verified front o2 sensor operation and engine coolant temp? If so, try replacing the fpr with a stock one but its also possible that the ECU is faulty and keeping the injectors open rather than pulsing them.

I didn't realize O'Reilly's even sold re-manufactured ECU's, maybe Steve will be able to help with this.

:dsm:
 

Batmobile

Proven Member
431
1
Feb 23, 2004
Olathe, Kansas
Yes its a fuel pump out of my '94 stealth twin turbo.

I forgot, my fpr is new oem(from o'reilys). So that has been replaced. I no longer own a stock turbo pump for a dsm, are yoy suggesting I try swapping it out?
 

Batmobile

Proven Member
431
1
Feb 23, 2004
Olathe, Kansas
front o2 WAS reading .91ish now that its warmed up, coolant at 209* its not getting above .70. and I have some crazy knock count, while the car is surging from 1100-500rpms. The counts in the 30's. And my cel is on for the maf.

After reviewing some threads on the MAF, I think my maf is actually bad. Now I own a 2g maf and harness and even the snorkel(I have owned prior 2g awds). I do realize a need a afc to do this. Or i might find a 1g maf some where.
 

gofer

Moderator
8,148
1,385
Feb 18, 2006
South Gilbert, Arizona
The front o2 is supposed to cycle from .2v to .8v at idle or does it move around a bit from .9v? What type of MAF (Hz) values are you getting on the logger?

A 0.9v signal from the front o2 sensor is RICH, that makes sense as to why you're getting poor gas mileage.

:dsm:
 
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