lack of power under heavy load
 

hey whats up guys, I just wanted to see if I could get a few more ideas. I swapped in a different set of injectors and a different wiring harness last week and when I put it together I had some issues. Most of the issues have been fixed by replacing a bad injector and a bad boost/pressure sensor. The problem that I'm having now is that I still have very little power in the high RPM's. The car will sometimes sputter up high but not all the time. It feels like the car is running rich. When I drive under medium load I have no problems but when you really give it gas it seems to bog down. When its bogging if I let off the gas just a little, I seem to get back the power. I have verified that the 6pi's are functioning properly and I've set my TPS via the Ohm method. I also think that the injectors are working properly. Could it be something with the throttle body? I switched a lot of stuff but I still dont seem to be able to fix this problem. BTW its an 88 gxl.

You may want to check the basics like fuel delivery, clogged fuel filter for instance.

Do you have good grounds for the secondaries, boost sensor at the ECU ? that's a common problem.

Hugues -

I regrounded the 4 ground spots on the ECU and it helped (3a,3G,2C,2R). I dont think it's a problem with fuel delivery because it doesn't exhibit the problems all the time. Under light and medium loads it's fine but under heavy loads it definitely feels like it's running rich as opposed to lean. I think it's either an electrical or a vac problem. what other things could make this happen?

oh yeah, just to give some other info. The car is also backfiring like crazy when i let off the gas in gear. It's like popcorn. in addition sometimes I have a wierd idle where its doing the common bouncing thing. ICould a problem with the ACV be causing some of these symptoms?

When is the last time you checked your timing? How about your spark plugs and wires? Do the plug wires have a good connection on the end of the spark plug? If it feels like its running rich when the problem occurs I would check the ignition and see what's up.

- Dana

the spark plug wires are brand new 10mm magnecors. I dont think its that because if i had a bad wire, you'd feel the sputtering throught the power band.

bump

ha..ha..:uhh:i know im a little outta place here....i drive a skyline...but anyway,i had the same problem in my car,half throttle was the best i could get,full throttle it would bog and sometimes chug!!horible!!i then replaced the fuel filter and HOLY SH!*$T!!!WHAT A DIFFRENCE!!i then cut the old one apart to check it out and absolutelly disgusting,i was sick to think my baby had to try and suck fuel throught that,i have an RB20DET with a FMIC,downpipe,3.5 inch exhaust,intake,BOV and took da CAT out,mine also pops when i left off the throttle or downshift,i think its just the fact that it might be running a bit rich and the exhaust is straight through.good luck

yeah man, i kinda also have the same thing still. mine seems to be more RPM realated than throttle position, i got no power above 6,500 or so RPM. I've changed the plugs, wires, fuel filter, and checked the timing and tps. i dunno....