Car still not running right...Anyone know what it could be

[colz89gt]

Heres the problem i've been having: car runs fine at idle but develops a miss under a load. Pulled the codes on the car and replaced the ECT,ACT, and MAP sensors. While i was at it i put a new TFI module on the car and also put a pickup in th distributor. The car has 24 lb injectors and a PMAS mass air meter which is brand new. The only other code i got was from the neutral safety switch which i already knew was bad and i disconnected it from under the firewall i disconnected the plastic connector that connected it to the clutch pedal. Could the neutral safety switch be causing this problem or not? I am stumped guys, we have even traced all the wires back to the computer to make sure none of them are bad or have been fraed we've even checked the pins going into the computer to make sure none of them are broke off. The computer that is in it is an A3ML i have an A9L on the way so i am going to put it in as soon as possible. As said above the car runs perfectly fine sitting the idleing but as soon as you mash on the throttle it develops a miss, you can let off on the throttle and get back on it and it will run ok for a second than fall on its face. The TPS sensor has also been adjusted to .97 volts. Anyone else have any suggestions, I know my best bet is going to be fix the neutral safety switch and pull the KOER codes, but i was just wondering if anyone else had, had the same problems....

[PaulFiveOh]

Of course you replaced, or at least checked the plug wires?

[AntiRice427]

Sound like a spark problem to me. Pull the plugs and see if one of them is loaded up with fuel.

[dedpedal]

Dont forget to check the O2 sensors. Mine had a slight miss under load that got progressively worse and it went away when I unplugged the sensors. I replaced them and all was fine in wonderland.

[colz89gt]

i have checked all that cleaned the O2s and all the plugs were gapped at .54 and still nothing cut the gap down less and its still doing it. i am stumped at what it could be either an injector stuck open or something with the computer....

[94gtvert]

Does it run ok at wide open throttle? My friend had a bad MAF that was a new part, it was right after we built his 306 so we had all new parts and had to do all kinds of trouble shooting before figuring out the MAF was junk, put on a new maf and it drove like a new car. His car wasn't throwing a check engine light or anything. If it is the maf it will run like crap, bucking and "missing" all the way until you get to WOT.

[colz89gt]

well we thougt that it might be the mass air flow we thought it might be a bad one from the get go, so we took one off another guys car and still didnt help. mine runs fine idling and if you rev it just sitting still, but as soon as you put a load on it it starts cuttining out. the car runs great if your just cruising along but as soon as you mash on the throttle is when it cuts out, if you let off of the gas and than get back in it it will pickup, but still doesnt run like its supposed to.

[PaulFiveOh]

It really really really sounds like a plug wire issue! Sounds simple I know, but I had the same exact symptoms. Can you swap all 9 just be sure?

[colz89gt]

Yea i am going to try that and see if that helps. I am running out fo things it could be other than a stuck injector. IDK what it is but its getting aggrivating as hell!

[Timido]

Make sure #5 and #6 plug wire are not touching each other. Also try swaping distributors with your buddy and run it. When the distributor housing gets worn out it causes alot of problems with spark scatter inside the distributor.

[colz89gt]

we did put in a different distributor. were going to swap a set of plug wires and also hook up a spare 6AL box and see what that does if that doesnt fix it its gotta be injectors.. I hope

[graysonracin]

If by chance your still running the stock catted h-pipe, the converters may be clogged. I had one that idled fine anf ran okay underlight load, but try to beat on it and it started missing, bucking and didnt go anywhere. If no cats, try the mass air like the other guys said.

[beentryin]

sounds like wires to me

[colz89gt]

mass air is brand new have tried three others off of friends cars that are running fine. still the same thing the meter on it is a PMAS unit thats brand new. no cats and its a x-pipe. were going to try to put a 6AL box on tomorrow to see if just maybe my stock igniton is failing and also try the wires and put in new plugs. if thats not its i am pulling the 24s out and swapping my 19s back in it to see what that does

[PaulFiveOh]

Hold on!

Do not simultaneously replace the plug wires AND the ignition box. Do the plug wires first, test it out, then if same results, plug in msd box and go from there.

[Buckeye]

Also have you watched the digital sweep of the tps if it has a bad spot it will do the same as well. Also what is fuel pressure under a load? pump may be weak. But yes start with the wires and a good cap and rotor too

[Buckeye]

if thats not its i am pulling the 24s out and swapping my 19s back in it to see what that does

Wait what mass air and computer is in the car ? if you just stuck 24's in with no matching maf and computer it will choke on gas

[colz89gt]

its a PMAS calibrated for the 24's i have a A3ML computer i have an A9L on the way with an SCT chip. i am not buying any of the wires or the box just borrowing it and trying it out. were going to do the plugs and wires first, than if that doesnt help put the ignition box on. if that doesnt help i guess i am going to pull the injectors later this weekend.

[colz89gt]

swapped out the injectors for another set of 24s, put stock regulator back on, tried an MSD 6AL box, swapped plugs and wires, even put a different pump in the tank, car still wanting to shut off when it gets under load. something that puzzles me is the car wont shut off when you unplug the mass air meter, we've swapped out computers twice with known good ones and still the same thing. the only thing i get now when i pull the codes is the neutral safety switch, but i dont think it would cause this. i am stumped and dont know what else it could be other than the wiring harness, any suggestions?

[facemelter71]

My PIP in my 86 took a dump.Check that.

[colz89gt]

what is the PIP and where is it located??

[facemelter71]

Year make and model with ALL the mods you have done.If you could list those,that'll be great.

[colz89gt]

all my mods are in my sig. , the only thing differnet now is that we put a stock pump in it yesterday to see if maybe my 190 was bad because i bought it used. well its still doing it. idk what it could be now other than maybe a blown head gasket or stuck lifter

[colz89gt]

The car runs fine in first gear you can tach it to 5600 and never cuts out , when you go to second the car will accelerate fine until you mash it when you do it falls flat on its face the CEL flashes and no power, when you let off on the gas and get back in it it will accelerate as long as you dont mash it, 3rd gear is the same as first no misses at all,4th gear does the same as second when you mash it. Could this be the neutral safety switch doing this or could it be some other sensor on the transmission.

[graysonracin]

Can you swap out coils with someone, didnt see that you tried that yet.

[colz89gt]

yep tried that....

[Buckeye]

Does it fall on it's face and stay dead or just stumble and come back? It sounds like fuel I don't know what is done to it but 24s may be too much I have seen a few people try to run them and it ack like you describe. put 19s and a stock maf in it. Plus what does fuel pressure do when it acks up? What happens if you unplug and plug the vac line to the fp reg (Does it make it worse)? What do the plugs look like if you mash it and keep it in the dead area for a bit?

Anyways you need to do more testing and less parts swapping, you may fix it but you will learn more and it will be more reliable if you learn to test first.

[colz89gt]

well we have swapped injectors and it still was doing the same thing, so i dont know what the deal is. we put the stock ones in as well as the stock mass air and it still did it. also put stock regulator back on. fuel pressure stays the same, we even took my 190 lph pump out and put a different pump in it and its still acting up. we have done each of these things one by one not just doing it all at once. the plugs look good each time we have checked them. when it does it the car completely falls on its face no power nothing the CEL even flashes. as soon as you let off on the gas and than get back on it its ok, unless you romp back down on it than it will do the same thing again. what i dont get is why it only does it in 2 nd and 4 th gear, and i also dont understand why when you unplug the mass air sensor the engine doesnt sound any different. its gotta be something in the wiring i think...

[mustang3091]

Was your intake new or used you may have a hair line crack in it or a blown intake gasket

[Katmandu]

Also have you watched the digital sweep of the tps if it has a bad spot it will do the same as well.I didn't see where you ruled out the TPS.

Do a sweep check and reset it and see what happens.

[colz89gt]

yea the TPS is new, and set at .97 volts, so is intake..

[Katmandu]

what i dont get is why it only does it in 2nd and 4th gear, .. You need to find a local Priest and have that car Exorcised! :eek:

I can't wait to hear what's causing all this havoc. :cool2:


.

[colz89gt]

you and me both hopefully will know something by the first of the week...

[Buckeye]

Get a pin out of the computer plug and check continuity for the maf. Might have a broken wire. Have you checked the codes?

[colz89gt]

pulled the codes and also pulled that pin out didnt check continuity though, i have another harness and am going to swap it out monday and see what happens.

[Buckeye]

Why check continuity if it is good no need for the extra work. What codes where in it?
Iwas also thinking about this and realized that the 2 gears it acts up in are both in the down position on the shifter, Do you maybe ether A. have a wire in the way that gets pinched when in 2 and 4 or B. have a after market shifter that the stops are out of adjustment making ack funny under load (Both mat be a streach BUT being you are so far away so gotta ask)

[Sparky]

Here's a dumb question, do you have it set to the right firing order? I'm guessing you have code 67? If so, it shouldn't affect driveability. All the neutral switch does is tell the computer when your out of gear so it can give it idling parameters so it doesn't die when you come to a stop . I've heard it said that code 67 can cause a hanging idle. Here's another dumb question, did the car use be an automatic? If you have the wrong O2 harness you can fry the computer through the neutral switch circuit. Since you had to replace all the sensors and the only one you have left is the neutral switch, since you unplugged it, seems all too familiar to me. if this is the case, don't plug it back in yet. Check to see if your computer is cooked because it might be running in FMEM mode (failure mode)If you have a multimeter, pull the ECM out and check resistance between pins 20,40,and 60...through pin 26 I believe. resistance shouldn't exceed 4-5 ohms anything greater , its probably cooked. Also, if you feel like there's a short somewhere, check the black and white connectors at the back of the plenum. Sometimes they get dirty and cause dumb stuff to happen.

[colz89gt]

i will indeed check those pins on the back of hte intake, i've heard them called salt and pepper shakers because one is black and the other white. thats a good point about the 02 sensor harness because i did get it off a car and the guy wasnt sure whether it was an automatic or not i will deffinetly check that out.. the computer was swapped out with two other computers the last of the two was in a running saleen car, and it still didnt change.. i cant help but think that neutral safety switch may be the culprit i dont knoow much about them, i do know the reason i unhooked it was because the car wouldnt start after it got hot say running for 5-10 minutes. what it would do was it would sit there and idle all day long but once it warmed up and u pushed the clutch pedal it would shut off.. so i d/c the actuator that connects to the pedal and taped it so it stayed pushed in all the time, know you dont even have to push the clutch to start it.

[Sparky]

It's not the switch itself, its the circuit its tied to. It shares the same signal return circuit as all of the sensors on the engine. The neutral switch runs through the O2 harness and goes to pin 30 on the ECM . If you look at a wiring diagram, it also ties into pin 46 (the signal return for all the engine's sensors). On an auto car, that circuit is for a neutral safety switch, and has 12 volts running through it every time its engaged to start the car. If you have an auto ECM like an A9P you can get away with it because its pinned different. On an A9L your supplying 12 volts to something thats more or less a ground, and it fries all 3 case grounds in the ECM, putting it into failure mode. You can fix this by re-pinning the O2 harness and it will all go away. Theres a little jumper wire that loops from one hole to another where it plugs into the engine harness. All you have to do is switch one end to the empty pin hole, I can't remember which one exactly, I'd have to check my EVTM manual. Your on the right path. I was in the same boat when I did the 5.0 swap into my ranger. I couldn't stop thinking about that neutral switch, but I every one else kept saying otherwise....that it didn't matter. They're only half right. If it was an original 5.0 5 speed car you wouldn't think about it at all. If your check engine light is flashing at you, its more or less saying "stop ignoring me dammit I'm hurt!" I hope you figure it out.

[colz89gt]

i will deffinetly look into this on monday. and let you all know the results. i've been messing with this thing since about october off and on, i hope i get this thing solved before long. thanks for all the help guys i'll let ya know what i figure out the first of the week..

[Buckeye]

Well shit that is a new one for me too. Learned something new today!

[colz89gt]

Swapped out the mass air harness today and didnt change a thing. Going to swap out the O2 harness tommorow and see if that does anything, and i also ordered the neutral safety switch but it wont be here till Thursday.

[Buckeye]

SO are you going to check the wireing and see if you fried the computer or keep tossing parts at it ?

[may93]

I really think you have more of a timing problem then anything else. Are you using the 13726548 firing order wiring in a counterclockwise rotation? Do you have a older motor that requires the 15426378 firing order? If you have gas,spark, timing, and air then the car should run. From what you mentioned it does run so I'd look at the timing more closely. Also check the fule pressure at idle with the vacuum hose unplugged and see if it around 38-42. It could be a faulty regulator that could cause a drop in fuel pressure being supplied to the injectors. And once last thing is your MAPP sensor connected and do you have the ground connected that runs from the harness to the body?

[rsmurf04]

I would agree with MAY93 sounds like timing is to advanced or retarded

[colz89gt]

Already have checked the computer its fine, we checked it yesterday. The bottom end is out of a 95, and we have checked the spark plug wires to make sure they're in the correct order. The adjustable fuel pressure regulator is off the car now and we have a stock one back on that is new. As far as i know all the grounds are hooked up, i have one grounded to the back bolt on the intake manifold and the other is grounded to the bell housing. I dont know whether it is possibly for it to jump timing or not but i havent pulled the water pump and stuff back off to check that maybe the next thing i do, if you all think that could be possible?

[may93]

When was the last time the car ran correctly? Was all the mods done before you bought the car or have you done them all yourself? If you can pinpoint when your problems started it might help with the diagnosing. I doubt it jumped timing unless you have a seriously worn motor but that doesnt mean its not out of time. Have you put a timimg light on it to see if it advances when you give it gas and did you set the timing with the spout connector unplugged?

[colz89gt]

Timing has been checked and is set at 13 degrees. I did all the mods to the motor my self the problem started after i put the injectors and mass air and fuel pump in it. But we have swapped out a set of good injectors one was a set of 24's the other were 19s. We also put a stock fuel pump back in because we thoguht the pump i bought might be bad, and the stock one we put in came out of a saleen and the only reason he swapped out his pump was because he had put 30lbers in it.

[may93]

Not to ask obvious questions but is the mass air meter plugged in and is it the correct one for your injectors? If your problems started after you changed those parts then it has to have something to do with your changes. Does the fuel guage hold pressure as you increase RPM?

[colz89gt]

I think we have the problem figured out. Unplugged the O2 sensor harness and took it down the road and it ran bettter than before still has a lil break up in acceleration but i think this was from the computer not getting a reading from the sensors. With the O2 sensor unplugged and when unhook the mass air the car will die it didnt do this before with the O2 sensor hooked up. I am guessing I had a harness for an automatic, i am going to get one this week and go ahead and order new oxygen sensors. Hope this fixes it.

[may93]

Isnt that the same harness you used before you changed the Mass air, Injectors, and fuel pump and it ran good? Normally the Oxygen sensors will just make it run rich or lean but it will still run ok. Hopefully you found your problem but I think something else is going on there. Which computer are you using anyways? Also if you bought any of your parts used double check the part #'s as people dont always know what they have they just repeat what others have told them and sell it as what they think to be true. Anyways wish I could be more help. Let me know when you figure it out as its driving me crazy.

[colz89gt]

No the O2 harness i got off ebay because mine was burnt into at the low oil sensor connector, so i just went ahead and bought a new one, and cant remember whether or not it is out of an automatic or not..

[Katmandu]

Not to ask obvious questions but is the mass air meter plugged in and is it the correct one for your injectors?X2!

Where did you get the MAF from ?? What size is it ?

Did you clean off the (2) tiny wires on the inside of it lately ? :confused:

[Timido]

Check your fuse links off your starter solinoid. From a wiring diagram there is one that is for the O2 sensors.

[colz89gt]

have any idea where i can find this fuse link off the solenoid.. is it along the firewall or what?

[colz89gt]

Anyone know exactly where i can find this fuse link? I replaced the O2 sensor harness with one from a manual and even changed the injector harness. The car does run better but still has a slight miss under wide open throttle. I did find a spark plug that had what looked like a hairline crack in it and could hear it arching, so i replaced those but havent ran it yet.. The car changes now when i unhook my mass air meter but it still will not die.

[Buckeye]

Go to the library and use there computers they have alldata on them you can print GOOD wire diagrams

[rsmurf04]

you can use your local CarX phone number as a user name and password to get on alldatapro.com

[347sc]

The fusable link are on the battery side of the soleniod. They have eyelet rings and black heat shrink.

[colz89gt]

Finally got the car running right, the EEC relay was bad and redid the fuseible links at the same time and that fixed it.. Thanks for all the help