okay so i've had this problem since i bought this car its a 1990 gtu it will backfire on command i give it gas let off and tap the throttle and it backfires i've removed the cat polution controll air pump and power steering but thats not the real problem the real problem is that when my engines under load the check engine light comes on and it sputters and the more i depress the gas the more power loss i have i had the car scanned and no codes are coming up but it's not always the same sometimes i can pull through 3rd before it'll come on and sometimes i cant get out of first.. any ideas? anyone elece have this problem?

 

Have you checked compression?

john ny

 

Just want to ask - are you sure it's back firing and not after firing? common misconception.

A "back fire" is ignition of fuel/air mixture in the INTAKE passage.

Ignition of a fuel/air mixture in the EXHAUST passage is termed "after fire"

 

yes i gess you could say after fire since it blows blue flames about a foot out the back and the compression is front 8.4 8.6 8.7 rear 8.9 8.8 9.0 i had that tester at the local dealer

 

the check engine light will come on if i let it idle to its weird would low fuel pressure do that the guys at the dealer think its a coil but wouldint that be more consistant this problem is completely random...

 

afm connection?

 

im sorry lol but whats amf short for? im not to up to date on my short forms

 

air flow meter

 

no i had it scanned that would come up in a code and i thought that was maf but i replaced that because when i had it scanned the first time that code and my metering pump came up but i bought a new maf sensor and there was a bad connection to the metering pump.

 

its hard starting to i have to hold it to the floor for it to start if that helps ... i just dont know what to try next i think im going to get my fuel pressure checked check my coils with an ohm meter and maby rip the tank out and check the sending unit...

 

x

 

my car just did this. it was the oil metering pump.

 

how did you fix it did you replace it because there ******* expensive would a full oil metering pump removal work then you just pre mix your gas right?

 

Your OMP is electronically driven by your ECU. If you remove it your ECU will cause the car to go into "limp mode." Your options are limited to repairing, replacing (new or old) or removing your ECU in place of a stand alone setup, which would allow you to do away with the OMP and open the doors for premixing. This is one of the vagaries of the S5, as S4's don't have this issue.

 

Tps