Murilli

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Alright, gaskets came in. Was planning on taking off the intake today... how-ever. I was on E and my tires were getting flat, so I took a risk and drove it to the gas station. It got me there, about 2 miles down the road, no stop signs speed limit of 30mph. Of course it felt like it had 10hp. It took a while, but I did manage 3d gear. Filled up the tank and tires.

On the way back... So when ever I gave it gas the RPMs would go down and surge back up continuously. It's been idling at 2k, but when I gave it gas, it would go down to about 1500, and bounce up a few hundred, and back down. It did this even in gear, even while moving, so the car would buck making it impossible to drive outside of idle. Long story short, I had to idle back going pretty slow... took about 20 minutes.

Anyways, when the car worked fine, it would do this every so often when I would start her up in the morning. I'd literally have to wait a few minutes until the throttle would 'work' and allow me to rev past 2k and drive to work. If I had my camera on me, I would have recorded this. In the past leading up to the day it pretty much died, it would do that weird throttle thing more often. Maybe this can help me figure it out!

Anyways, sorry for the long post, I felt as if I should be as detailed as possible. Any suggestions please let me know! With my limited knowledge on automotive repair, I'm beginning to think it's a fuel issue? Maybe one of the injectors is clogged?

Murilli

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Started her up today. Idled at 1k for about 10 seconds, then slowly began to creep up to 1900, where it stayed for a few minutes. Then it started the surging Idle again. I have it on video this time, i'll post seperately after this. Played around with some vacuum lines and what not, looking for a leak. Unplugged the TPS, the surging stopped. And the idle went down to 1k. Turned the fan on, and the idle continued to drop. It almost died so I plugged the TPS back in, and the surging continued.

Unplugged the TPS and plugged it back in, and shook the TPS connector, for what ever reason. The surging stopped. It kept a very smooth idle at 1800. Ran for about another 20 minutes without it changing. Also, I was able to rev the engine much more smooth, even when it was surging. Reved it to 7k, without any backfires. Weird. I still plan to delete the EGR, how-ever I'll re adjust the TPS tomorrow, it was reading a little over 2 volts. I'll upload the video and pictures of the engine bay if that helps.

satch

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The voltage output of the TPS is dependent on the engine temperature if the thermowax/fast idle cam is working properly. It should not read 2 volts but one volt "if" the engine is completely warmed up. Usually a twenty minute drive will completely warm up the engine and idling it for a couple of minutes won't cut the mustard. You might want to inspect the plug connection to the TPS if jiggling the harness changes on how the engine performs.

Murilli

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Computer is having issues, will try to upload tomorrow.

I checked the TPS after I'd say at least 20 minutes, I didn't drive around because well it has no power, takes about 20 seconds to get to 30mph pedal to the floor. kind of a difficult situation! Hmm maybe it is the wiring harness, there's a spot near the MAF where the wire looks almost chewed up like. I'll try and test that tomorrow, luckily I work with a ton of electricians and mechanics! I'm starting to think maybe it would just be a good idea to replace all the wiring anyways, I mean it can't hurt, and it's good for the long run anyways. Where would I find that though? Thanks again Satch!

satch

iTrader: (1)

You can ohm out the TPS wiring to give you a heads up to any of the wiring being problematic. As far as a replacement harness the TPS wires are part of the Emission Harness. Buying a used one from a fellow board member and reinstalling one is not a simple matter. The TPS has but three wires. One is a ground, one is the Vref which provides the sensor w/5 volts w/key to on and the G/R wire is the output wire sent to the ECU. If in the even you needed to replace or redo one of these wires it would not be hard at all to do.

Murilli

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Alright, played around with her yesterday. There is a wiring problem for sure now! It has to do with the main wiring that branches off to the TPS connector. Just moving it around I was able to get the idle to change from 1800 to 1400. I can also control the surging with it as well. Now my question is, could this affect the injectors? Might be what's causing the huge loss of power. Also, tried to adjust the throttle screw on the TB with it jumpered. It literally did nothing! Had it all the way in and out.

I let the car Idle for about 15 minutes, took a 10 minute drive (though slow) and let it idle for another 15 minutes. I did adjust the TPS after that and got it to 1volt.

It still backfires at 6k, but not as loud and not as often. I did have a short about 3 months before all this started happening, just replaced the fuse and went on driving as normal, didn't think much of it til now though. Anyways I have two pictures of the engine bay and throttle body, not sure if there's something or if theres something I'm not noticing. [IMG][/IMG] [IMG][/IMG]

satch

iTrader: (1)

You need to measure the voltage on the TPS wires as mentioned in post #55 as you jiggle the harness to see which wire(s) is problematic and then repair that wire. Chances are an analog needle type multimeter will show you a voltage drop off better than a digital one but the digital meter might be good enough. And of course make sure the plug connection is a solid one and it would be best to test these wires from the Emission side of the harness and not the sensor side of the connector.

Murilli

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Alright thanks Satch, luckily I only have an analog multimeter. Makes sense though, could poor wiring be the cause of a power loss?

satch

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Poor wiring could be the cause of a lot of things.

Murilli

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So, checked the wiring today, turns out, one of the wires going from the harness to the TPS connector is having issues. Also checked a few other wires, for the most part I didn't find anything I was looking for, except the, I believe it's the Air control unit? It's above the exhaust manifold attaching to the lower intake. It doesn't seem to get any continuity, but my air pump is gone, so would it be an issue either way?

So, the reason why I haven't blocked off the EGR yet is because I'm moving in 2 weeks to Michigan, and well I don't want to take her apart and get caught up in something, thus not having it driveable to get shipped.

Anyways, I'm more convinced there's a vacuum leak which is causing the high idle. The car starts up great! hits 1k RPMs, and slowly creeps up to 2k. stays there. (Cold start not working anymore?) Adjusting the idle has no effect on the RPMs either. I've checked with spraying TB cleaner on all the hoses today, with nothing. I was really hoping for something!

Anyways, there's no hesitation anymore!! I can rev her to 7k all day long with out backfiring and no roughness either. Smooth like before! She does back fire on deceleration though, but nothing bad. The TPS read 1 volt today.

So we're making progress! Once I'm in Michigan, I'll have the time to work in depth on her all day.

satch

iTrader: (1)

Fast Idle Cam is responsible from slowly pulling down the idle speed from 1500 to 750.

Which TPS wire is problematic?

W/o an air pump you will burn up the catalytic converters if equipped.

Murilli

iTrader: (1)

Alright, the TPS wire that's to blame is actually the connector I believe, it's on the harness side so nothing with the TPS. It's the wire (the flat one rather than the two parallel ones)that goes into the connector that connects to the TPS connector. It's just really loose. Simply fix really.

No Cats on this baby.

I have a video of it starting today.

86 GXL rx7 starting up - YouTube I'll mention that this was the worse start I had in a while, it normally starts right up and goes to 1k then creeps up. It seems like it had a different plan today. Should I prepare myself for a possible broken seal of some sort?

satch

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You can always measure the compression of the engine if you feel the need to. And the wire at the TPS which you seem to think is problematic is the G/R wire which is the sensor output wire and thus it is important for the ECU to be getting the correct reading of to run properly.

Murilli

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Alright, finally moved back to Michigan! Did a compression test today. Front rotor housing got 3 pulses between 50-60PSI. Rear housing got about 3 pulses of 60-65PSI. I had it tested before... never saw the guy do it, but he did say my compression was fine. What could this be?? Hard to say since all pulses are about even.

satch

iTrader: (1)

What did he mean by 'fine.' The readings you just provided are poor to say the least and perhaps the testing was done improperly. A compression test is supposed to be done w/a warm engine and not a cold one in case you weren't aware of that.

just ray

Answering your questions sorry, must have totally skipped over them! I will check the voltage of the pin 2I of the ECU, how-ever would the water thermosensor be causing all this? Also, in neutral I can rev the engine up to 4k ( I haven't really tried higher, incase of harming the engine) with it backfiring throughout the revs, the rpms don't climb as fast either, it's almost as if there's some resistance keeping it from shooting up there, but it still climbs, just not as fast as before this madness!

The link you sent in regards to the timing issues, I'm not understanding if I'm to pull out the CAS then adjust it, or adjust it while the vehicle is idling. Is it possible to adjust it without the timing indicators, they must really be worn off or never put on it. Thanks again Satch, you have to excuse my lack of mechanical knowledge.

Ccarlier

did you ever find an answer to your problem