seawolf18

iTrader: (1)

I have a 91 Trans AM 305 TPI 5-speed. The car is running really rough, and has a dead spot at part throttle. Once you hit the dead spot, you have the feather the gas or it will die. You can also push the gas past the dead spot, but it still runs really rough.

I replaced the plugs, cap, rotar, and wires. I also made sure the firing order is correct on it. I checked the fuel pressure, and it was between 44-45 psi on the gauge with the engine off. I also ohmed out the fuel injectors. All the injectors were 14.x ohms cold, and 15.x ohms hot. I used a timing light and varified that all cylinders are getting spark, and checked the timing. It is at six degrees with the wire unpluged.

Replacing all the parts did not affect the way it runs at all. I am at a loss here. All I can think of now would be a dead cylinder. The engine does not knock while running, and has oil pressure. I guess I will have to do a compression test next on it. What else would cause this thing to runs so bad? I also do not have a SES light, and no codes in the computer.

Tuned Performance

iTrader: (92)

have you done a ohm sweep on the tps ?

seawolf18

iTrader: (1)

I have not, however the previous owner put a brand new one in.

seawolf18

iTrader: (1)

Well im digging deeper into this thing. When the car runs it now sounds like it has a massive exhaust leak on the passenger side. Upon further checking, I found all of the runner bolts on both sides loose. I took them all out but one by hand. I pulled the vacuum line off of the fuel pressure regulator, and it smells like gas. Looks like that's bad also. I found one injector leaking after pulling them out of the intake while still attached to the fuel lines. I also found the fitting that screws into the intake for the PVC valve loose.

I ordered some new injectors and a Fuel pressure regulator from South Bay Fuel Injectors. Looks like i;m waiting on parts now. I am also going to get rid of all of the smog BS thats in the way. In the picture, are these still the factory multec's on this thing?

Tuned Performance

iTrader: (92)

those are not the original multi-tech's, make sure you got the 10% discount for being a tgo member.

seawolf18

iTrader: (1)

Hmm wonder what they are then. All they say is 19 lb/hr on them, no brand name. Someone has been deffanally messing around in there. I remembered the discount. Thanks for reminding me though.

seawolf18

iTrader: (1)

Looks like after a little more digging they are ACCEL injectors. Are these prone to failure as well?

ASE doc

Those would be the Multecs famous for causing problems. New injectors and FPR, seal up that intake and you should be in good shape. Of course a compression test is always a good idea.

ASE doc

ACCEL injectors are worse than the Multecs.

seawolf18

iTrader: (1)

I'm now waiting on parts. I'll post back when I get this thing back together. Hopefully it fixes it this time.

ASE doc

I apologize for misidentifying the injectors as Multecs. I was only looking at the nozzles. The bodies are obviously not Multecs.

seawolf18

iTrader: (1)

Thats cool. I found a part number on the injectors. They are indeed accels. I believe old style ones? Anyway, looks like the guy I bought it from had no idea on what he was doing. He threw a bunch of parts at it, it didn't fix it, so he sold it. I don't believe in the shot gun approach on fixing cars. Gets spendy really fast.

ASE doc

We all try here to help members avoid that. Time spent on diagnosis is priceless.

seawolf18

iTrader: (1)

Got the car back together tonight. Installed new injectors, fuel pressure regulator, and upper intake gaskets. The miss is gone. I do still have a dead spot at part throttle. Still no SES light. I checked for vacuum leaks, and found none. I made a video of what is doing here. http://www.youtube.com/watch?v=_OSnL-rMbQc I'm running out of ideas on what could be causing this.

ploegi

Have you verified that the voltage from the TPS progresses smoothly? (analog gauge is best for this test.)

seawolf18

iTrader: (1)

What is the procedure for checking the TPS? Do these cars require an idle relearn once you disconnect the battery? I remember I had to do a idle relearn procedure in my 92 Beretta 3.1 I owned back in the day.

seawolf18

iTrader: (1)

Okay, found the TPS test procedure. Is the TPS sensor any different from the non speed density cars? The local parts store wants $90.00 for a TPS for my car, but a non SD car TPS is only $30.00. I will try and get it tested some time tomorrow.

seawolf18

iTrader: (1)

Tested the TPS sensor this morning. The reference voltage was 5V on the bottom pin of the connector like it should be. I then back probed the center pin. The voltage with the throttle closed was at .631 volts, and 4.21 at wide open. While slowly pushing the throttle open, the voltage reading would hesitate a little in some spots, and went OL(out of limits) on the meter for a split second in one spot. I think it needs a tps.

In reference of my top post, can you install a non-speed density TPS in a speed density car. The cost difference between the two is crazy, being the speed density one is much more expensive.

Tuned Performance

iTrader: (92)

The only difference on the two tps is that a 85-89 maf has elongated holes and that makes it adjustable. The 90-90 sd the holes are not elongated. You can use a 85-89 tps and adjust the tps to .66

Tuned Performance

iTrader: (92)

That glitch is not good post #5 it should be a smooth sweep. I prefer using a analog vom and have the pigtail disconnected and turn it to ohm and do a sweep.

seawolf18

iTrader: (1)

Thanks. I;m going to go get a TPS and throw it in.

Tuned Performance

iTrader: (92)

I don't recommend throwing it maybe the old one.

19GTA92

I'm having trouble with my vacuum lines on my 1992 trans am 305 5 speed. Could you tell me where they start and end please?

Tuned Performance

iTrader: (92)

you might want to start your own post and not hi jack.

https://www.thirdgen.org/forums/tech...iagrams-i.html

FNFAL308

iTrader: (1)

I don't know how other feel on here, but I don't recommend washing your engine with the TPS on the car. The only ones I ever had go out was when they got wet. I even covered one with plastic and duct tape once and water still got to it.

seawolf18

iTrader: (1)

I got the new TPS in today. When I start the car when it was cold, it ran great. No dead spot reved just fine. When it warmed up and came down off cold idle, it started doing the same thing again. Dead spot and spuddering at part throttle. You have to feather the gas or it will die when it starts spuddering. If you rev it up when warm no dead spot, but when you let off the gas, the rpms go way down and it almost dies, but the car catches its self and starts idling again.

I rechecked the TPS, and wiring with my meter and all is fine. I then tried set the minimum idle. I jumped the aldl terminals and waited for 30 secs like the procedure says. I then unplugged the IAC. the car was very hard to start and will not idle. The only way to keep it running was to keep your foot on the gas. I plugged the IAC in, and it took a few tries starting it for it to idle again. When I had the car apart, I did clean the IAC and passage in the throttle body. The car also seems to be running really rich when warmed up. to the point of burning your eyes if you stand behind it. I am at a loss again it seems.

Tuned Performance

iTrader: (92)

Since you have no way to datalog the cts could cause it to run rich. You might want to pull the pressure regulator hose and check for any sign of fuel.

seawolf18

iTrader: (1)

Pulled the fuel regulator vac line. No gas smell. Also just replaced the regulator. I ohmed out the coolant temp sensor and it read 1.486K ohms on the meter. The engine at about 100 degrees according to the gauge. What should the resistance value of the coolant sensor be?

Tuned Performance

iTrader: (92)

Tuned Performance

iTrader: (92)

Another test although new or refurbished injectors you could have a leaking one. after the car sits over night I would prime the fuel system koeo a several time and pull the plugs looking for wet plugs.

seawolf18

iTrader: (1)

Checked the plugs after priming the fuel system several times. Plugs were dry.the cts was $10 bucks at the local parts store so I picked one up.its running good cold but crappy warm so I think its not going into closed loop mode.

Tuned Performance

iTrader: (92)

The cts will effect the engine from going into closed loop. Since you said it had had the injectors replace someone could have silicone poisoned The oxygen sensor. Disconnect the sensor after the engine warm's up. I like to set up my vom and rev the engine off idle to insure the exhaust is warmed up and the sensor is active. A O2 sensor signal stuck at 450 mV is an indication of an open O2 sensor circuit (signal wire) or faulty O2 signal ground.

Another way of testing to see if the car goes into closed loop it to get it warmed up. Enable the diagnostic mode bye jumping the ALDL A to B and run the car at 12-1600 for a minute. The Check engine light will turn off once in closed loop.

Tuned Performance

iTrader: (92)

Check engine light will flash as follows: 2 times/second = Open Loop
1 time/second = Closed Loop

3. After it is in closed loop the Check engine light will turn off and on according to the O2 sensor input.

Off all the time or most of the time : LEAN
On all the time or most of the time : RICH

ploegi

How old is your O2 sensor? If the problem starts showing up about the time the engine should be going into closed loop....... that's the first thing I would look at. Slow/wrong response will make it run funny....

Also, MAP, or MAF?

ninetyone

iTrader: (2)

IIRC , any tps voltage over 4 volts at WOT is ok. At idle my voltage is at .71 which is also fine.

seawolf18

iTrader: (1)

The car is a MAP. I will test the O2 sensor circut and also jump the aldl to see if its going into closed loop.

ninetyone

iTrader: (2)

yeah,but if you jump the aldl like that and drive it, it wont stay running when you take your foot off of the gas pedal. If it even starts up at all.

Tuned Performance

iTrader: (92)

It has been years since I have used the field service mode. I had assumed it works as a alternative to using a scanner or data logger on a P4 730.

ninetyone

iTrader: (2)

I have only used that mode to check for codes. I accidently started my car with the A and B pins jumped once and it would not stay running unless you had your foot on the gas pedal, fans would be running and the car may knock under acceleration. I would not recommend trying to drive your car around in this mode. Put a scanner on it instead

Tuned Performance

iTrader: (92)

No one said to drive it in diagnostic mode

seawolf18

iTrader: (1)

I put the car in diagnostic mode today after I warmed it up. The SES light shut off, then blinked once per second. So The car is going into closed loop mode. I decided to start over on checking things to make sure I havn't missed anything. I rechecked the plug wires, and firing order. They were both fine.

I then checked the timing again again. I unpluged the tan wire and put the timing light on it. The car was timed to six degrees. After looking at it for a while, I finally noticed that it was set at 6 degrees retarted, not advanced! Who ever was working on it before me timed it the wrong way, so its 12 degrees off. I pluged the advance back in, and the advance wasn't getting past 0 degrees until after 2000 rpms.

I then ran out of time and had to get to work. First thing tomorrow i'm going to set the timing back to where its supposed to be. I slapped my self up side the head for not noticing that the first time I checked the timing. Hopefully this has been the major problem all along. That and the leaky fuel injectors\bad fuel pressure regulator I replaced eariler.

ninetyone

iTrader: (2)

that is the timing scale,there is no 6 degrees retarted,hope u get it right

seawolf18

iTrader: (1)

it was at -2 when I checked it. All the numbers are hard to read on it. so It was 8 degrees off.

seawolf18

iTrader: (1)

Retimed the engine to 6 degrees with the wire unplugged.car runs better bit still had the dead spot. After timing it I checked the timing to make sure it was advancing with the wire plugged back in. it was advancing when I hit the throttle. I did notice while it was idling that the timing was jumping all over the place.I did also notice that I can turn the cap about 1/8 inch either way withthe hold down bolt tightened all the way. The cap hold down screws were also tight.

I then checked all the connectors on the ecm. They were all tight.I then did the tap test on the ecm with the car running no change in the way it was idling.I did notice the car has a reman ecm in it.

ninetyone

iTrader: (2)

it shouldn't turn at all ,maybe get a new bolt and a lock washer

seawolf18

iTrader: (1)

found out why the dist. was loose. Pulled the dist. The base plate the module bolts to is loose. This was apparently a problem a while back. Someone took a machine screw and screwed through the base plate from the bottom, and wedged it against the main shaft. The only reason I could possibly think of why someone would do this, would be try to keep that plate from moving back and forth. The module looks pretty new in it. Looks like I need to get a new dist. for the thing now.

Tuned Performance

iTrader: (92)

Don't get one of the cheap chinese ones off Ebay !! they are junk I had one and the icm was bad to start with, I replaced that and a few weeks later had running issues and it was blowing oil under the cap. The best think todo is goto the junk yard and find one off a f-body 87-92 tpi or tbi or tbi truck. I would use your new icm and put thermal paste under it and you might invest in a new icm pickup. There are two bodies on these some tbi trucks and tbi cars had a lager body that will not work yours is the smaller one. Cardone remanufactures these but that's a risk in itself. The shaft endplay should be set to .014" and .015" (cold)

seawolf18

iTrader: (1)

Finally found a dist at one of the area salvage yards. Will hopefully get it in on Tuesday. this is what the previous owner did to the dist. that was in it. I've never seen anyone try this before.

Tuned Performance

iTrader: (92)

um never seen that done. It obviously dousnt keep accurate timing.

http://www.ebay.com/itm/87-Camaro-Z2...r#ht_500wt_717

seawolf18

iTrader: (1)

Got the new dist. in and timed. Car ran great no dead spot. Took it out for a test drive. I had it on the floor in second gear then the car cut out and started bucking real bad. The check engine light also came on. Took the car home, and on the way it was like riding a bucking horse at low speeds. Pulled the codes and code 34 for the map sensor came up. Checked and made sure the map sensor connector was tight and the vacume line was connected.

Started the car back up, and the check engine light went off, but the car is idling low and the rpms keep going up and down like its searching for an idle. If you tap the throttle now it surges real bad and dies, unless you floor it. It was also hard to get it started. I had to hold the throttle open for it to start then it does its idle thing like I described.