Weird Idling issue.....

[OnMy2ndE30]

I just replaced my timing belt and water pump, intake gaskets, valve cover gasket and rocker plugs, new spark plugs, cap and rotor, vent hose from valve cover to throttle body, ICV hose to throttle body, throttle body gasket, air intake boot and rebuilt 19# yellow top Mustang 4 pintle injectors. Now I have a problem. Before all of the work I did, I had an extended crank issue and the engine would run rough until I gave it gas, then smoothed out. But it would stay running. When I started to put it all back together, I remembered that most throttle position sensors collect oil after all the miles put on them. So I used carb cleaner and sprayed it out and let it dry overnight. I put everything back together and started it up. It didn't take long for fuel to get to the injectors and it started, then promptly stalled. It ran like crap at first. It ran really rough but finally somewhat smoothed out. It finally ran at idle, but then all of a sudden, the rpms dropped out from under it, like the fuel was shut off, surged a time or two, then stalled. If I was out of the car and started it, the engine would stall very shortly after it started because I wasn't giving it gas to stay running. I had the tps adjusted in the middle, then decided to try adjusting it. I moved it all the way clockwise and heard a click in the tps. That is where I left it and the car started and idled, then stalled. I would rev the engine to 3-4k rpms, then slowly let it come back down to idle. It wold idle fine for a few minutes, then out of nowhere, it wold drop out, surge, then die. Did I screw up my TPS? I have double and triple checked everything: all connections and hoses. I have searched, but I can't find where anyone has had he same issue as me....PLEASE HELP!!!!

Preston

[89 e30]

Do you have a chip or and bigger maf? 19lb injectors can screw with the idle if no chip

[OnMy2ndE30]

Like screw with it so badly it just dies after about a minute of smooth idling? No chip or MAF conversion. I looked for symptoms of a failing tps and it describes some of the issues I am having. I know the ICV and the AFM are both good as well.

[TS87325IS]

You should hear a click from the tps as soon as you crack open the throttlebody, and then when you put it back to closed you should hear the click again. Do that with the engine off and your ear close to the throttlebody to see if it is in the correct position.

[jlevie]

Hearing a click from the TPS at the right point doesn't mean that the idle switch is good. You need to test it with an ohmmeter or a test light.

I really doubt the engine is going idle properly until you get a chip meant to be used with 19lb injectors.

[TS87325IS]

Hearing a click from the TPS at the right point doesn't mean that the idle switch is good. You need to test it with an ohmmeter or a test light.

I really doubt the engine is going idle properly until you get a chip meant to be used with 19lb injectors.

Yes this is correct, but to function properly, it must be correctly adjusted as well. :-)

[OnMy2ndE30]

Hearing a click from the TPS at the right point doesn't mean that the idle switch is good. You need to test it with an ohmmeter or a test light.

I really doubt the engine is going idle properly until you get a chip meant to be used with 19lb injectors.

I agree that I wont get the full potential of the 19 lbs injectors without a chip, but when it is idling for the very brief time that it does, it runs silky smooth. I talked with a few techs at work and they pretty much told me I trashed the tps when I attempted to clean it out with carb cleaner. D'OH!!!!!!!!! Nobody in this city of over 1 million people, including our crappy ass dealership, has it in stock. I can get it tomorrow from a small indy BMW shop.

[BMWamongJDM]

I know this may sound stupid but I had the same issue or sound like the same issue. Check your spark plugs are all in order 1to1 2to2 etc I had that issue I felt spoiling dumb but it can be something like that especially if it sound like its miss firing

[TS87325IS]

It will run fine on those injectors without a chip, i ran 30lbers on mine with a stock chip. You may have to tighten the black cogged wheel in the afm a click or two to smooth it out a bit but thats it.

[OnMy2ndE30]

OK. I tested the TPS and it was reading at WOT all the time. Bad TPS. Installed a new Bosch TPS and same issue. If I run the car in the higher rpms, it is smooth as silk, and we are talking 5-6k range. If I let off the gas when it starts to buck, and ease back into it, it smooths out. I basically had to drive in 2nd or 3rd gear on the highway at insane RPMS to keep it cleared out. The plugs are BLACK with carbon ( they were installed Sunday) and the tail pipe smells like raw fuel. I am going to swap the injectors back over and see what that does.

[OnMy2ndE30]

Just swapped the old injectors back into the car and it runs like a champ now. No bucking and stuttering. I used to have an extended cranking issue before all of this. Sometimes it would start right away, then it would take 5-10 seconds to start the next. I attribute that to the faulty tps I had. Like I said earlier, it was reading WOT all the time. I guess now I need a chip to use the 19lbers I bought....more to come.....

[Gregs///M]

That's strange. I run 19lb 4 hole pintle ends but Bosch brand in my M20. Everything else is OEM except Supersprint exhaust and my car runs fantastic. Better running than my OEM Bosch injectors.

You have to be sure your TPS is adjusted while installed on the car. 3 pins. Between two pins you should have continuity at rest. No continuity at 20%-100% throttle. Vice versa when the throttle is at full throttle between the common pin and the other pin. The bentely manual and ETM manual has great step by step process how to test.

Like the guy above said, listening to the "clicks" is not enough. You must have electrical contacts. Also the mechanics who said spraying carb cleaner in the TPS ruined it might be good with engine mechanics but noobs with engine electronics.

Cleaning the TPS is OK with carb cleaner and I have done it many times. It clears out the oil that accumulates inside of it. However, the contacts for the micro switches are sealed so those will never get cleaned. Once the microswitches do not work, the TPS will need to be replaced or an electrician, like myself, can perform the swap of the internal micro switches.

[OnMy2ndE30]

That's strange. I run 19lb 4 hole pintle ends but Bosch brand in my M20. Everything else is OEM except Supersprint exhaust and my car runs fantastic. Better running than my OEM Bosch injectors.

You have to be sure your TPS is adjusted while installed on the car. 3 pins. Between two pins you should have continuity at rest. No continuity at 20%-100% throttle. Vice versa when the throttle is at full throttle between the common pin and the other pin. The bentely manual and ETM manual has great step by step process how to test.

Like the guy above said, listening to the "clicks" is not enough. You must have electrical contacts. Also the mechanics who said spraying carb cleaner in the TPS ruined it might be good with engine mechanics but noobs with engine electronics.

Cleaning the TPS is OK with carb cleaner and I have done it many times. It clears out the oil that accumulates inside of it. However, the contacts for the micro switches are sealed so those will never get cleaned. Once the microswitches do not work, the TPS will need to be replaced or an electrician, like myself, can perform the swap of the internal micro switches.

I had a tech on my team at work who is an ex BMW tech test the TPS and it was reading WOT all the time he said. I replaced it and that part is good now.

Another update though. I took the car to work this morning and halfway to work, it started it's crap again. Bucking and stuttering under load. We have an old school V-30 scanner at work and tested all the components on the car. All of them passed and tested good. I started the car and tried further testing and nothing found wrong. I let the car run and evved it up repeatedly to get it to try and stall ot and reproduce what it does, and it ran like a champ. We thought maybe the AFM was starting to fail, and since I have another one at home, I was going to swap it in and see from there. I disconnected the diagnostic link cable and plugged in the cap for the DLC......it freaking started acting up. I quickly unplugged the cap and the engine smoothed out. I thought maybe a fluke, so I plugged it back in and it stuttered and stalled out. Took the cap off again and started it, it ran great. I drove home without it on and the car never missed a lick. WTF is the deal? I know the cap has pins in it to connect circuits and stuff, but it runs great without the cap on. Any insight to this??????