Acceleration issues
 

I just recently replaced the FPD, my vacuum hoses, and had my injectors cleaned (witch hunter), had to replace my two primaries. Now my problem is I got it all back together, fired right up but when I went to drive it the car wont accelerate under WOT if the RPM's are under about 3-3500 RPMS. If I accelerate slowly to 3000, and then run it WOT it drives just like it should. If I try to accelerate WOT under 3k the motor the car starts bucking and bogging down. I checked all the vacuum hoses half a dozen times, all electrical connectors are plugged in, everything seems correct. Any help is appreciated, there are a couple of things I still have to do on the car, install my boost gauge, and replace fuel filter. So, maybe the fuel filter is the problem but you guys let me know what you think.

And the year of your car is? Turbo or NA?

I'm going to assume 2nd gen, so check your grounds. http://www.aaroncake.net/rx-7/grounding.htm

Sorry about that, no it's a 94 fd.

If this began from the first time you ran the car after doing the hose job, I would suspect it's something that happened when doing that job. You said you replaced the primaries - were they cleaned also?

Unfortunately I once had an experience where I did a hose job, got my injectors serviced, and one of the injectors got stuck after the cleaning. Since the primary injectors work alone until 3500rpm, that's a possibility. It's not something to ignore, since a stuck injector causes a lean condition and under boost that can destroy the engine.

Dave

I don't think it is the primaries because the car idles perfectly and drives fine under a light load. But no I didn't have them cleaned, I had to buy new primaries because the other ones were leaking from internal seals.

What other vacuum lines could cause these symptoms, I have checked the FPR lines, the turbo control lines, the doule throttle and all apear to be working correctly. I am going to try to get my boost gauge hooked up this week so I can see if it is a boost issue.

Boost problems cause loss of power but usually not bucking. Changing the fuel filter and installing the boost gauge is a good idea.

Unfortunately I've had injector problems before and they are quite similar to your symptoms. More load = bucking. Are your primaries brand new, or were they bought used?

The primaries are brand new from RX7store, I am going to check the grounds again, I didn't have them tight the first time I started it but tightened them later, it alleviated some of the problem. Could this problem be caused by a bad plug or wire, I just checked the wires and they could stand to be replaced also.

It's possible. Other sources to consider might be the TPS.

Check the ECU for codes just in case it's registering there.

I checked it and all I got was an egr code, but I havent checked since. Also my CEL doesn't work, so I have been jumping the TEN and GRD pin and connecting my analog voltmeter to the FEN terminal is this correct, I found it on here somewhere.

Can the TPS just go out of range, I haven't adjusted it or even touched it other than to unplug it. I just drove the car and the bucking seems to be subsiding, but when I attempt to accelerate WOT it doesn't go, the RPM's just stay where they are at. I am wondering if the secondaries are leaking and causing a flooding issue the car smells like it is running rich, but I was hoping to get this tank of old gas out and put some fresh stuff in it and see what it does.

I'll agree with using up the old gas. If the car is driveable I'd burn it up. In an FD that should take about 100mi. :)

What are the effects on these cars of having old gas running through them, this car sat for about five weeks while I was working on it.

I've let my car sit for 5 weeks many times.

The fuel lines were disconnected for 2 of them, don't know if that makes a difference. I drove it down to about a quarter of a tank, cleaned all my grounds again, and pulled the codes again got code 16. Will the O2 sensor store a code if it is disconnected, I disconnected it and tried to pull the codes again and only got code 16. I am wondering if something is going on with the ECU and or the wiring harness.

Crusty wiring harnesses are no fun. I've also been there and done that.

Dave

I just looked through the FSM and I am wondering if I hooked up a ground wrong. If you are looking at the back of the UIM there is the grounding strap that connects to the clip on the back of the fire wall, there is a second ground that the O2 sensor is wired into, does that bolt onto the same bolt as the grounding strap or does it bolt into the hole in the middle of the UIM? Wonder if that is the problem.

I think they both ground to the same point at the back of the UIM.

Dave

Ok I am going to give that a try, maybe that would explain the super rich smell from the car.

Ok, so I switched the O2 ground and it helped the running rich part. I took it for a drive and it seems to be a turbo spooling issue, almost like it isn't building boost below 3K rpms. I am going to try to get the boost gauge installed tomorrow and post the results, and hopefully that will point to the problem.

Ok, so I keep getting code 16 EGR fault, can this effect my acceleration or put the car in a limp mode state?

I also have EGR code and there are times were my fd hesitates under 3k. Have you checked your MAP sensor? I found that the tiny clamp that suppose to hold the vacuum line tends to come loose, even if you just budge it by mistake. Well most of my hoses are pretty much dry rotted. Runs fine again as soon as i plug it right back on.

As for the EGR code, i still havent tried to figure it out yet.

I believe, it is also normal for the FD to hesitate at 3k, but not from idle.

It will not cause limp mode but it will cause driveability problems. See the FSM page F-236

Sounds like you need to resolve this EGR issue. You might be able to just swap in a 93 non-Cali ECU, which doesn't look for the EGR at all, if you want to research that option.

Dave

I just replaced all the vacuum hose including the MAP sensor hose, but the sensor that triggers code 16 just tells the ECU if the EGR fully closed or opened and that it completed the cycle correctly. Oh, and the car is not just hesitation, it completly cuts acceleration, almost like it is cutting fuel. But I am somewhat certain the EGR has something to do with it because once I clear about 3500- 3800 the car starts accelerating, the EGR cut off is 3850 rpms; but on the other hand a bad EGR should be causing idle problems. If it was stuck fully open and venting all the gas back to the UIM how would that cause a pure lack of acceleration, I can see how it would cause the pungent gas smell, and the code 16, but what sensor would it be affecting to completly stop the car from accelerating? I have considered getting a non-Cali ecu or just buying a PFC to save the hassle of doing it later, but I dont just want to put a bandaid on the problem. If the EGR solenoid wasn't working correctly it should throw a fault, but the FSM says it isn't a stored fault so I am going to have to pull the solenoid rack again and check them all. Thank you for the help and I will kepp you posted, but if someone has had an EGR malfunction and knows the symptoms I would love to hear them.

Kevin

If you arent too worried about emission issues, than try just capping off the EGR vacuum line. Just a suggestion.

Here it is: http://www.rx7.org/Robinette/egr.htm