speed racer Posted August 14, 2014 Report Share Posted August 14, 2014 checked for injectors leaking?i Link to comment Share on other sites More sharing options...
Edde Posted August 14, 2014 Report Share Posted August 14, 2014 (edited) I'm not giving up! It just occured to me that we haven't checked the IAT sensor, its in the MAF housing. It's used in the fueling equation. You should be able to disconnect the MAF plug and check it with an ohm meter but it is somewhat confusing because you have to check between a green wire/red stripe and black wire/white stripe and there are two of each of those in the connector AND you have to check it on the MAF side of the connector not the wire side. I just went out and checked one of my cars, if you unplug the connector and lean over to look at the pins in the MAF side so the locking tab is on the bottom its the lower left and upper right pins. Mine was 29 Kohm at room temp, check it cold and then drive until it goes wonky, pull over and check it again. Yes. Most important input device in the system. You can also test it with a hair dryer. Edited August 14, 2014 by Edde Link to comment Share on other sites More sharing options...
questtuner82 Posted August 15, 2014 Author Report Share Posted August 15, 2014 I'll check it when I get a chance really busy last couple days but the maf is a remanned one I put in a few weeks ago Link to comment Share on other sites More sharing options...
questtuner82 Posted August 16, 2014 Author Report Share Posted August 16, 2014 So what should the reading be on the iat sensor when the car is warm? I get a reading of 28 kohm cold and 30kohm when the car goes bonkers Link to comment Share on other sites More sharing options...
StarquestRescue Posted August 16, 2014 Report Share Posted August 16, 2014 fsm says 2.7 k at 68* and .4 k at 176 degrees. I prefer to check the voltages at the ecu with the components connected. Link to comment Share on other sites More sharing options...
StarquestRescue Posted August 16, 2014 Report Share Posted August 16, 2014 The voltage at the ecu would be 2.5-2.7 at 68*, 1.5-1.7 At 104* and .5-.7 volts at 176* But. Is the fuel pressure still dropping under boost after the car is good and hot? Link to comment Share on other sites More sharing options...
StarquestRescue Posted August 16, 2014 Report Share Posted August 16, 2014 Typical air intake temps for open filters under the hood at 80* would be about 105 moving and about 130-140 stuck in traffic. Link to comment Share on other sites More sharing options...
questtuner82 Posted August 16, 2014 Author Report Share Posted August 16, 2014 I'm still using a factory air filter canister. And using the 88/89 maf canister thingy Link to comment Share on other sites More sharing options...
questtuner82 Posted August 16, 2014 Author Report Share Posted August 16, 2014 Scott says that the iat sensor could cause the issue and that it also uses it for the fuel readings. And yes I still get fuel pressure drop but the car is starting to run a little better after all the changing I've made with sensors ecu ect. It now takes about 35-40 minutes for the car to miss in boost. My knock sensor was tested and tested bad so could this be all my issue Link to comment Share on other sites More sharing options...
scott87star Posted August 16, 2014 Report Share Posted August 16, 2014 Knock sensor will just cause timing to be pulled back, that won't make it buck or otherwise run like crap. Link to comment Share on other sites More sharing options...
StarquestRescue Posted August 17, 2014 Report Share Posted August 17, 2014 (edited) Factory 12a turbo. And 10 psi boost. When I fire it up and drive it cold it runs/boosts fine 20 minutes of drive time it starts to act up and gets progressively worse. It starts at about 5lbs boost and about 2200-2500 rpm then gets worse as I drive it to the point of anytime I bring it in to boost like even 2lbs it starts to break up.If you are telling me that fuel pressure is dropping at 5 psi boost at only 2500 rpm? Then i say there is still a fuel delivery problem, and will continual to harp on it till we prove that the gauge is intermittently bad. Which i feel is unlikely, or the problem is found and corrected. A wide band afr gauge would be quite helpful now. I suggest you find another gauge to try. Borrow a test gauge plumb it up and tape to the windshield. You can space the back off the hood up to make room for the hose. http://www.sears.com...P&mktRedirect=y http://www.amazon.com/OTC-5630-Fuel-Pressure-Test/dp/B000R5IASC/ref=sr_1_1/190-8320294-1862742?ie=UTF8&qid=1408241649&sr=8-1&keywords=fuel+pressure+test+kit Edited August 17, 2014 by StarquestRescue Link to comment Share on other sites More sharing options...
questtuner82 Posted August 17, 2014 Author Report Share Posted August 17, 2014 I'm going to go to advance auto and get the loaner tool fuel pressure tester and see what it shows. Right now I don't have money to plumb in a wide and but I can tell u that my new plugs have 150 miles on them and they show a lean condition so I am not getting fuel like I should be somehow. Link to comment Share on other sites More sharing options...
Edde Posted August 17, 2014 Report Share Posted August 17, 2014 I've re-read the thread and yes if fp is dropping like that it's not sensor or electric related unless the signal to the pump is interrupted, which it appears is not the case. Assume the tac doesn't drop like a stone when the issue presents. Mike C used to describe a de-lamination of the internal high pressure fuel delivery line that could wreak havoc on fuel delivery and be very difficult to figure out. Don't know how the heatup would relate though. I would expect it to be either all the time or really unpredictable, not after a certain warmup period. I've had a stuck open, gooey egr valve and clogged piping that would prevent the car from even maintaining a constant rpm. It would hold a few seconds on the smog test then stumble. It doesn't sound like this is similar from your description but just putting it out there. Link to comment Share on other sites More sharing options...
questtuner82 Posted August 17, 2014 Author Report Share Posted August 17, 2014 Egr is deleted. And fuel lines are stainless steel braided from f/p to t/b mixer so none of those are the problem. Link to comment Share on other sites More sharing options...
ucw458 Posted August 17, 2014 Report Share Posted August 17, 2014 Just curious, where have you tapped in for your fuel pressure gauge? Link to comment Share on other sites More sharing options...
questtuner82 Posted August 17, 2014 Author Report Share Posted August 17, 2014 On the back side of the throttle body mixer the port towards the firewall Link to comment Share on other sites More sharing options...
questtuner82 Posted August 21, 2014 Author Report Share Posted August 21, 2014 Ok so just for s**** and giggles I changed the knock sensor and it runs better now. Although it still has fuel psi drop issues which I found out was the relay in the f/p rewire. It's running good now , but after I did the tps/isc reset it idles at 1200rpm and now I have a flat spot right above an idle and when I get to that point it starts to buck. Any help or suggestions what's causing this Link to comment Share on other sites More sharing options...
Edde Posted August 21, 2014 Report Share Posted August 21, 2014 Get the idle down to 8-900 and make sure the tps output range is .50v at idle and 5v WOT. Also if you haven't, do a sweep test on the tps and look for spikes/flats. Link to comment Share on other sites More sharing options...
questtuner82 Posted August 21, 2014 Author Report Share Posted August 21, 2014 How do u adjust the idle on these damn things???? I adjusted both screws the one on the throttle body and the one on the linkage and no difference and I even took the throttle cable off and makes no difference. It acts like a damn air leak but I've checked over and over and it's all good no leaks anywhere Link to comment Share on other sites More sharing options...
ucw458 Posted August 21, 2014 Report Share Posted August 21, 2014 How do u adjust the idle on these damn things???? I adjusted both screws the one on the throttle body and the one on the linkage and no difference and I even took the throttle cable off and makes no difference. It acts like a damn air leak but I've checked over and over and it's all good no leaks anywhere Then you just messed up the TPS/ISC reset by adjusting those points. You adjust those in the beginning of the TPS/ISC reset then never touch them again. Link to comment Share on other sites More sharing options...
Edde Posted August 21, 2014 Report Share Posted August 21, 2014 Yeah UCW just called it. The procedure is very specific. Gwen says use the FSM and I agree in this case. Link to comment Share on other sites More sharing options...
questtuner82 Posted August 21, 2014 Author Report Share Posted August 21, 2014 Ok so here's what I just tested I have .5 on the tps and sweep test is good at wot it is 5.0-5.1 now the isc seems to be the issue. When I turn ign on at full temp and go to test the isc per isc test and reset it will test .9 but when I put the m/m on the green as + and black as - the isc motor will activate and spikes to 2.3-2.5 on the m/m and when I disconnect the m/m the isc motor activates again. Then check again it starts at .9 but then activates the isc motor with the m/m and goes back to 2.3-2.5 again. wt.... is going on???? Sorry for language but this car is pissin me off its ready to go to the shredder any day now Link to comment Share on other sites More sharing options...
Edde Posted August 21, 2014 Report Share Posted August 21, 2014 Why put the meter on those wires? Pretty sure the green/black test is on the tps connector. You want .9 on the isc AT idle. Maybe I didn't understand. Link to comment Share on other sites More sharing options...
questtuner82 Posted August 22, 2014 Author Report Share Posted August 22, 2014 Read the tps/isc reset writeup it tells u to check the voltage t the isc on the green and the black wire. Ok anyways my ecu keeps pulling the tps code but the tps checks good good sweep test and tests in car shows .5v with ign on and wot is 5.0-5.1 volt so it's in specs I did the full reset again the car idles at 900-950 but the ecu ends up pulling tps code.(5) I've reset this a couple time already today and all tests show what needs to be there and the isc doesn't show the .9 at idle like it should but shows 1.1-1.3 even thought I should have the reading of .9. I still have the flat spot above idle and if just sitting there and touching the throttle it surges between 1100-2200 and keeps doing this so I don't know what is happening Link to comment Share on other sites More sharing options...
StarquestRescue Posted August 22, 2014 Report Share Posted August 22, 2014 Check the tps voltage at the ecu. If it is not getting there the ecu can not read it. Link to comment Share on other sites More sharing options...
Recommended Posts