Robftw Posted August 21, 2013 Share Posted August 21, 2013 The car has stock efi with the cold start injector removed. Recently rebuilt motor, timing is set properly as it should be from the factory. I'm having an issue with an extreme rich running issue off idle, so much so that the plugs become wet and it dies. ive checked the tps and at idle the center & far right prong touch. after about 1/4 throttle or about 1500 rpm it releases the prong and starts to touch the far left prong and goes pig rich and dies, is this my problem? I can't find a definitive answer. Quote Link to comment Share on other sites More sharing options...
Robftw Posted August 21, 2013 Author Share Posted August 21, 2013 I've gone over the tps and set it to factory, the afm has not been tampered with. all injector clips are corrosion free and fire the injectors the distributor, cap & rotor are all brand new. the plugs are also brand new. I just put new 7mm wires on it too and still the same problem. It gets spark, fuel and just wont rev over 2k. when the tps is unplugged I can get it to 3k rpm but it cuts out. Quote Link to comment Share on other sites More sharing options...
Robftw Posted August 21, 2013 Author Share Posted August 21, 2013 I should also mention I never had any problems until I replaced the plug wires Quote Link to comment Share on other sites More sharing options...
ctc Posted August 21, 2013 Share Posted August 21, 2013 Did you ohm out the new plug wires? Quote Link to comment Share on other sites More sharing options...
NewZed Posted August 21, 2013 Share Posted August 21, 2013 Take the connector off of the ECU, find the pins to the TPS, and test there to see if it's working right. Test the coolant temperature circuit also, use the chart in the FSM to see if the resistance is correct for the temperature. It will take a little bit of work to figure out which pin is which at the connector and to piece together the information from the Engine Fuel chapter of the FSM, but once you do, you'll know if the ECU is getting the right information to run the engine. http://www.nicoclub.com/FSM/ Quote Link to comment Share on other sites More sharing options...
Robftw Posted August 21, 2013 Author Share Posted August 21, 2013 I will do that, in the mean time with another set of brand new plugs it will start run to 3k and then stop. the injectors are throwing so much gas into the engine that it will start and run for 5 seconds with all of the injectors unplugged. Quote Link to comment Share on other sites More sharing options...
NewZed Posted August 21, 2013 Share Posted August 21, 2013 Run an extra length of fuel line between the pump and filter through the cabin by the driver's seat. With a pair of pliers squeeze the line to stop all of that extra fuel from entering the engine, as you drive. With practice, you'll probably get up to 3500 RPM. Of course, the trade-off is no more texting while driving. Worth it though, to be back on the road. Quote Link to comment Share on other sites More sharing options...
Robftw Posted August 21, 2013 Author Share Posted August 21, 2013 Haha, I wish it was that easy. im thinking its leaking injectors, just put a vacuum gauge on it and it sits around 21-23 between 700-900 rpm. (I do not have a bouncy idle, I adjusted it) Quote Link to comment Share on other sites More sharing options...
NewZed Posted August 21, 2013 Share Posted August 21, 2013 Not sure why you're equating intake vacuum with leaky injectors, but 21-23 is a good number. At least you have a measurement to work with. I've seen quite a few injectors and only seen one actual leaker. And it was an external leak from a crack. Even if you had a leak, it wouldn't be so much that it floods the engine. Probably not your problem. High fuel pressure could be though. Good luck. A few more measurements would probably show the problem source. Quote Link to comment Share on other sites More sharing options...
Rob240z Posted August 21, 2013 Share Posted August 21, 2013 I had the same thing happen to me once before. It wasn't easy to figure out because no engine codes were triggered. In my case the coolant sensor was giving cooler readings to the computer than it actually was. This made the computer choke the throttle body, which is what it should do until it warms up. You can check it by disconnecting the coolant sensor wire. If it's reading wrong that will allow it to run pretty much normally until you replace the coolant sensor. Sometimes it just needs to be cleaned. It would have been an easier fix if the sensor just stopped working and tripped a code. Also, if you floor the gas during startup on most fuel injected cars it actually will cut all fuel. This should help to start the car in your scenario. You plugs are probably fouled by now and should be replaced when you figure this out. Quote Link to comment Share on other sites More sharing options...
NewZed Posted August 21, 2013 Share Posted August 21, 2013 In my case the coolant sensor was giving cooler readings to the computer than it actually was. This could be right. This made the computer choke the throttle body, which is what it should do until it warms up. This is wrong. You can check it by disconnecting the coolant sensor wire. If it's reading wrong that will allow it to run pretty much normally This is definitely wrong. Sometimes it just needs to be cleaned. This is close. The connections can add resistance. They need cleaning. You seem to be mis-translating some modern car concepts to the old EFI systems. Rftw really just needs to break out the FSM and a multimeter and do some work. Quote Link to comment Share on other sites More sharing options...
Robftw Posted August 21, 2013 Author Share Posted August 21, 2013 Just tried the sensor, same thing happens. I can disconnect the tps and it'll rev to 4k and cut out, but the second I plug it in and rev it blows black smoke and dies. Quote Link to comment Share on other sites More sharing options...
Rob240z Posted August 21, 2013 Share Posted August 21, 2013 You most likely are right that I am mis-translating some modern car concepts. I agree that he should do what you say and use the FSM. I have a 240z with no fuel injection and have very little experience with 280z early FI. I do have a lot of experience with early FI in other cars though and I think the example I gave can help with at least understanding in general what could be causing the problem. Basically, a sensor related to temperature is probably not performing correctly and might be the source of the problem. Testing those sensors would be a good thing to do. Here is a good thread that might help. http://www.classiczcars.com/forums/fuel-injection-s30/13077-280z-running-rich-how-fix.html Quote Link to comment Share on other sites More sharing options...
Chris83zxt Posted August 22, 2013 Share Posted August 22, 2013 (edited) I didn't see what year we're talking about. I'm assuming L28 NA since it's early EFI. Did the NAs have cylinder head temp sensors? My l28et goes too rich to even run if I unplug it, so it might be bad or have a bad connection. Edited August 22, 2013 by Chris83zxt Quote Link to comment Share on other sites More sharing options...
Mack Posted August 22, 2013 Share Posted August 22, 2013 I would suggest looking at the CHTS, not the coolant temp sensor. The CHTSm if you have one, should be on the spark plug side of the head between cyls 5 & 6, I think. Towards the firewall for sure. sounds like the connection could have been disturbed while changing spark plugs. What year is your car? Quote Link to comment Share on other sites More sharing options...
Robftw Posted August 22, 2013 Author Share Posted August 22, 2013 76' no sensors near that area Quote Link to comment Share on other sites More sharing options...
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