kozman

I replaced up to a grand in parts and my car is still running like poop. I have 89 TA, 5.0 TPI, auto, 2.73 rear, 75k miles.
Here it is in a nut shell. Poor idle, bucking and jerking, horrible gas mileage, hard starts. I've replaced the following in the last year.

Rebuilt MAF
Relay's - MAF, burn off, fuel pump
O2 sensor
Knock sensor
New 52 BBK TB
Battery
Cat
Plugs, wires, Dist, pick up coil, ignition module
FIC 19lb injectors
Fuel filter
Timing set
TPS set

The only other thing I could think of is the fuel pump, but was told pressure is fine 42psi. The fuel pump howls but was told it normal...HELP

Car is in the shop again today, it's killing me. Any suggestions would be welcomed

Gunner823

iTrader: (2)

I hope you're not replacing all these parts on the advice of that shop, or I'd be finding a new shop.

Make sure your ECM/prom is good.

jamon8

iTrader: (3)

connector to the MAFS

Ninety-One

Do a compression test, also check the oil, make sure its not milky.

GTA90X

iTrader: (2)

I recommend checking the ECM before doing anything else. I bought an 89 Formula years ago that had very similar issues. I had a friend who is a GM technician stop by and check it out. Although there is a trouble code for a failing ECM, he said it almost never pops up. When he hooked up the scanner, all the sensor values were within the proper parameters, but the ECM wasn't processing the data consistently. It was basically all over the spectrum and constantly trying to adjust. Replaced the ECM and all was good after that. Good luck, problems like these are always the worst in my opinion.

kozman

I never thought of the ECM because I got a few SES codes last year(33 and 36) and replaced EGR(forgot to mention earlier, replaced that too) and MAF burnoff . The codes disappearared after install and never had any SES code issues since. I will try to get hold of ECM and try that, any place you advise to get an ECM on the cheap?. My wife is killing me on how much this 'hobby' is costing us.....

kozman

OK, just stopped by the shop for an update and the mechanic said" this is kicking my ***"

He ran a bunch of test, ECM checks out good, TPS, IAC , injectors are all good. He came back with three issues.

1) Fuel pressure is good at start and load but he said he pinched the line and the pressure dropped which he said could be an issue with the check valve in the fuel pump which is causing a hard start.

2) He thought the 52 BBK throttle body could be throwing the idle off due to the ECM being programmed for the stock 48 throttle body.

3) Smelled gas from rear tank are, said it's the purge valve(plastic thingy)that should be replaced.

The other think I found odd was that he thought the timing should be set at 10 degrees, I thought 6 degrees was stock, can someone confirm 6 degress is correct.

He also thought the car should be tuned by a performance shop due to the performance parts on the engine. The only performance parts I have are a 52 BBK TB and a 3 inch cat back to 80 Flowmasters - doesn't sound "high performance" to me.

Any help or comments welcomed, he wants to get the car out of his shop tomorrow....

GTA90X

iTrader: (2)

1) If I understand this correctly, common sense says pinching a fuel line would would cause a pressure drop downstream. Not sure what this guy was trying to accomplish by doing this. Ummm...wait a second. How did he pinch a steel fuel line? I know my TPI doesnt have rubber fuel line anywhere.

2) The stock ECM has more than enough capability to compensate for the increase in airflow that you get from a 52mm throttle body.

3) This may be true but I dont think its the cause of your problems.

also, 6 degrees is the stock setting, but I have often read that TPI's seem to benefit from a setting of 8 degrees. I know I haven't given you a fix to your problem but I honestly don't think this mechanic has any idea about what is really wrong. From the list of parts you have changed, it looks like he was grasping at straws hoping to find a fix. As you know, it gets very expensive trying to chase this stuff down.

One thought tho and I don't see this on your list. Find out what your coolant temp sensor is telling the ECM. I once had a similar problem. The CTS was telling the ECM the car was running a ridiculously low temp. But because the the reading was within the parameters of the sensor, it wasn't issuing a trouble code. Good luck, let us know what you find out...
----------
also, is the car running rich? black smoke from the tailpipe? any trouble codes?

Stephen

iTrader: (12)

52mm TB on a mostly stock 305? Swap back to your stock TB & see what happens. Thats a BIG mouth for your 305.

GodSpeedGTA

iTrader: (1)

When i first got my GTA, I had some rough idle problems ect.. Kinda like what you are having. It eventually died one day and wouldnt restart. I took it to my personal mechanic ($35 an hour) and spent $700 for him to go through all the wiring and redo what ppl had spliced and bypassed etc. for the past 10 years or so of the cars life.

The car has run great since (when it starts). I have startup problems sometimes but im pretty sure its got something to do with my battery. I have a new high power Duralast and my volt meter only shows like 10.5-11 volts when i first put the key in and then it hard starts and takes a lot of tries. But, if i just hook it up to another car it starts right up.

My car is about to hit 200k so hard starts are to be expected. Ill be working on getting a new motor very soon, but $$$ is $$$.

kozman

GTA90X,

Maybe I wasn't clear on point 1), I believe has was saying when the key is turned on I get pressure at the rails(42psi) but it leaks down due to the check valve not working correctly, I think that make sense, therefore my hard starts. I may has misspoke when I said "pinch".

2) I agree, the ECM should handle a 52 TB. Stephen you may disagree, but many TGO members use a 52 TB on a 305. I can't swap my stock since the bushing were trashed, that's why I changed it.

3) Should be a non issue, it's getting changed today.

That leaves me with the timing issue, does 10 degrees sound correct?, he said he tried 6 and 8 degrees but it kept pinging. He thought 10 is fine.

Finally, no black smoke or rich condition, no codes either. Have not tried the CTS because the thermostat is stock and the dual fans kick in at 210-210, never have a temp issue.

87350IROC

iTrader: (2)

Sounds to me like you are getting jerked around by your mechanic. If 6 or 8 degrees of timing is causing the motor to ping, 10 degrees will be even worse.

Here is what you should do next.

1. Connect a fuel pressure gauge to the fuel rail. Pinch off the return fuel line with pliers or vise grips, it is the smaller of the two rubber fuel lines on the drivers side of the engine bay. Just put a rag over it and squeeze away. Now have a friend prime the fuel pump. Does the pressure hold at 42, or does it drop immediately to zero? If the pressure does hold now, you need to replace your fuel pressure regulator, it is leaking. If it still does not hold pressure move to step 2.

2. Now remove the pliers from the fuel return line. Have a friend prime the fuel pump again. As soon as your pressure reaches its highest point, pinch the fuel supply line. Does the pressure immediately drop to zero? If yes, you are leaking fuel out the fuel rail somehow. This can come from leaking fuel injectors or broken fuel pressure regulator diaphragm. If the fuel pressure regulator diaphragm is broken you will get gas traveling through the vacuum line that attaches to the fuel pressure regulator and into the intake plenum. Check to see if this vacuum line smells like gas. If the pressure does hold when you pinch the supply line, you are leaking gas somewhere between the pinch point and the fuel pump. Most likely candidates would be a busted check valve in the fuel pump, leaking pulsator, or cracked in tank fuel hose. All three of these will leak fuel back into the tank. In this case you will need to drop the fuel tank and replace these parts, no fun.

I would fix your fueling problem before moving on to other parts. It would also be useful to test fuel pressure while the engine is running and even when the car is driving. Your engine pinging is probably due to insufficient fueling. Also put the timing back to 6 degrees stock.

Don't worry about the throttle body its not the cause of your problems.

kozman

Thanks for the input IROC but my mechanic said he tested your point 1 and the regulator was fine.

On point 2,he did the test and said the check valve is most likely faulty.

He did test the pressure at prime and load and it tested fine.

My questions is - if i have a faulty check valve, will this cause the engine to break up at 1,000 - 2,000 rpm's??.

As far as the timing, he pulls his info from ALLDATA.com, which I believe is a website shops use to get specs on all cars. He inputted my make , model, ect in the data base and low and behold, the site said timing should be 10 degrees !! (I saw the print out for myself last night.). I mentioned I thought 6 degrees was stock, he said he will get second opion on that.

I tried to do a search on base timing on this site, most people said 6 degrees is factory base but also seen 0-10 as base(confusing). I can't find any solid documentation, I have a Haynes manual at home, it gives you the procedure to set timing but does not state 6 degrees is stock. Does anyone have any proof in writing that 6 degrees is stock, I dying here...

Dale

iTrader: (12)

Check and make sure you have good ground at all points, on all sensors and ecm, and battery to motor.

The 52mm may cause funny idle. But it should have a setscrew where you can adjust it.

Is 19lb stock for a 305?

Also make sure your IAC is moving in/out correct. I had alot of problems and it turned out my motor was moving.... But the pintile had popped out of the drive motor and jammed shut.

1bdbrd

iTrader: (1)

Here's the thing. At this point I don't think it matters what the original timing setting was because he said it runs ok at 10* but pings at 8? That doesn't make sense to me.

From here I would replace the fuel pump before anything else. If pressure bleeds down then its either your fuel pressure regulator or your pump. I would lean more towards the pump because you said its fairly loud, plus not many have problems (that I have seen) from the stock FPR. Another test is to hook a fuel pressure gauge up and tape it to the windshield and drive around. If the pressure drops under load then its the fuel pump.

GTA90X

iTrader: (2)

Look at the sticker under on the underside of your hood. That should confirm your base timing of 6*. As far ALLDATA.com, I got suckered into subscribing to that site. In my experience, all it had was generic information and generalized "how-to"'s that could be applied to any vehicle. I'm not trying to bring you down even further, but I think your mechanic may be doing more harm than good.

87350IROC brings up a valid point in regard to the timing. I think I would try his ideas on checking the fuel pressure before you let this mechanic work on anything else. Good luck man, and keep us infromed.

kozman

Thanks for the replies but as I said he did the fuel pressure test both at start and load and the pressure was good. Two things I heard obout 3rd gen fuel pumps - 1) they always howl and 2) either they work or they don't. So I'm at a stand still here about the pump as I don't want to drop anther 500 bills to replace the pump if I don't have to.

He checked the IAC and TPS, they were off a bit but nothing that would cause a major issue, he correct back to spec.

As far as the timing, I'm still not sure on the 10 degree issue, I don't have the sticker on the hood so I can't confirm if 6 is correct. I'll try 10 out for a while to see how it runs, if any problems, I can change the timing back to 6 myself if I have to.

I'm going to pick up my car in a few hours, I have not heard from him today so I assume he did not find anything else of importance.

Stay tuned(no pun intended)

Stephen

iTrader: (12)

My 87 & 89 GTA stickers both read 6 degrees. Tell him to set it back to 6, just to check if he doesn't agree.

And make sure he is disconnected the spark advancewire plug. If he is setting the timing without disconnecting the plug, your timing will beWAY off.

87350IROC

iTrader: (2)

Just because he said he did the test doesn't mean he did it right. First you mention the pressure goes to 42 on prime then bleeds down to zero. Then later you say he did the supply line pinch test and it checks out ok. So which is it. If it bleeds down right away something is wrong.

Also, the stock base timing is 6 degrees, that is a fact. To check timing start the motor, unhook the inline tan/black wire connector on the passenger side firewall. Connect timing light and check timing. It should be set to six. Reconnect the wire connector and shut off the motor.

If the motor really is pinging at 6 degrees timing it will absolutely be much worse at 10.

As for the fuel pump, you heard wrong. My pump has never made any noticeable noise. Also they can slowly fail. I recently diagnosed a bad fuel pump in my own car. It was only supplying 23 psi as idle. Certainly not a complete failure. I used the tests I described before to figure out my pump was bad.

Honestly it sounds like either your mechanic doesn't know what he's talking about or he is jerking you around. I would get the car back and do some of these simple tests yourself. We should be able to diagnose your car with a volt meter and a fuel pressure gauge, total $40 investment.

kozman

Well, just got the car back and it looks like it's fuel pump related. I thought it was a timing issue but he reset the timing to 6 degrees and said the car ran much worse and put it back to 10 degrees.
The car seems to idle fine but when rolling to a light the rpm's bounce around from 600 to 400 and sounds like it's gonna stall. The other problem is when I take off out of the hole, it bucks and jerks between 1,500 and 2.000 rpm(like it's running out of gas). If I take off normal I don't have the bucking problem, it only seems to happen when I floor it. Also at highways speeds, the car runs great at 3,000 plus rpm's, I mean from 50 to 80mph, it moves out with no problem.

My mechanic suggested I do the fuel pump but at this point I'm gonna wait and hope I get the summer out of the pump before it dies. It still drives but i guess it's not wise to drive with a pump on it's last legs, I'll take my chances as I only use this car on weekends and a car show here or there.

Keep ya posted, any other ideas welcomed

87350IROC

iTrader: (2)

Sure, why don't you spend $70 on a pump and fix it yourself? It sounds like this car isn't a daily driver anyway. Then you'll be able to drive your car without worries for the rest of the nice season.

GTA90X

iTrader: (2)

LOL kozman, don't put it off man. Chances are, its gonna die real soon if thats the problem. Nothing will ruin your weekend faster than Bubba's towing hooking up to your baby in the middle of the road or at a car show. Think he's gonna care about your ground effects and paint? Do yourself a favor and take a Saturday and swap it out. The peace of mind will be worth it.

kozman

A few more questions and then I'm putting this to rest.

If my car breaks up ONLY some of the time , is that related to timing or fuel pump?. Let me explain, as I mentioned before, my car would break up during accelaration but not all the time, one day it would rip with no problems, the next day it could act up....strange. .So is that timing or fuel?


It has been advise that I do two things, first- reset timing to 6 degrees and see if that changes anything. Second, put a guage on the winshield and test the pressusse myself.

I will try this and report back

..on a good note, it's still $1,000 as he do not charge me for the last visit...

Dale

iTrader: (12)

I would say more fuel related then timing. The times your describing it has problems, is when max load is on the pump.

GTA90X

iTrader: (2)

fuel pumps are weird

snardos

When you say the timing is better at 10* instead of 6* is that advanced or retarded because it is supposed to be 6* advanced. It wouldn't make sense for it to ping at 6* advanced and not at 10*.

And if the timing has to be that retarded then there is definitely something wrong with the fueling.

8T9 BANDIT

i would still find another ecm, put youre prom in it, then see what happens. it still sounds like an ecm problem still.

kozman

I was told it's set at 10 degrees BTDC

snardos

Ok, so the timing isn't retarded but something else on the car is.

kozman

Well said Snardos, I'm gonna try the "tape the guage to the window" trick and see if that leads me to my fuel pump issue.

8T9 Bandit, I see you're from LI, I don't have access to another ECM, stop by the MC Donalds in Forest Hills for cruise night on Tuesday's and I'll swap yours !!!!.

snardos

If you get from 45-50 PSI at WOT then I would say your fuel pump is working fine for now. Mine is also a little noisy when I first turn my ignition on if the pressure has bled down but I haven't noticed it when the car is running.

kozman

OK, I just purchased a pressure guage and will try to check this fuel pump issue for my own sanity. A few questions

1) When I check the pressure at turn key(engine off), do I remove the line from the regulator or leave it on. I should see 42 psi at turn key, correct?. When I turn the key off, what should I expect to see - pressure holding or bleeding?

2) When I tape the guage to my windshield and take it for a ride(I assume with the line to the regulator hooked up), should the idle psi be lower than 42?, like around 38 or so. I assume the psi should be steady(38-42) during driving, if the pressure drops under load, I would think the fuel pump is dying.

please confirm if the steps above are correct

87350IROC

iTrader: (2)

When just priming the fuel pump there is no engine vacuum so it doesn't matter if the vacuum line is hooked up or not. When you prime the pump you should get ~42 psi. When you turn the key off, the pressure should hold for hours. It may drop a few psi when the pump stops, but then it will hold.

If the pressure doesn't hold, do the tests I described earlier.

Do the non-driving tests first. No sense in potentially doing damage to your motor if you don't have to.

kozman

OK, I did the tape to the windshield trick today and it doesn't seem to be the fuel pump. I hooked up the guage and at turn key it was 44psi. I then did at test drive with a friend, good thing the guage had a 6ft. hose so he was able to hold the guage in the passenger seat. Well, at normal driving, the pressure was steady at around 36-38 psi. When I then hit on the gas a bit and the pressure ticked up to 40-42psi, so that seems normal - correct.

But here was the problem, after driving for around 20-30 minutes I would stop the car to a complete stop and then hit the gas and launch out of the hole, at around 2,000 rpm's the car would break up (buck and jerk) but the pressure was still steady at 38 psi. So I'm confused of why would it break up every time at 2,000 -2,500 rpm, but the psi would not drop!!, to me it doesn't sound like a fuel pump problem - does it?.

So it seems like an ignition problem, as I said the plugs, wires, ignition module and fuel injectors were changed about a month ago.

Need help on this one....

87350IROC

iTrader: (2)

Yup, sounds like its not a fueling issue. Did the pressure drop after you turned off the motor?

First make sure none of your plug wires are burned.

Then I would suspect the ECM or PROM.

You can pick up an ECM from this site, ebay, or a junkyard. You should be able to get one for less than $70. The ECM's in these cars are really crappy, so it wouldn't hurt to have one around anyway.

Dale

iTrader: (12)

I doubt this is the problem, but what about pickup coil?

Also, as I mentioned before. Check all your ground wires in the harness, as well as your battery ground to the block.

kozman

Pick up coil was replace a few weeks ago, so i doubt that is the issue.
The car is still breaking up, took it for a Sunday morning drive on the highway and she still breaks up at 2,000-2,500 rpm's. It seems to run ok when your cruising but when you hit the gas hard it breaks up...can't figure this one out. The wires seem to be away from the manifold and don't see any burns or breaks.

I may think it electrical, the prior owner had a car alarm and it was removed but wires are all over the place, maybe something is getting grounded or something.

My friend knows an electrical wizaed who will take a look at it in a few weeks(he's on vac), for now it starts and runs as long as I don't jump on it.I'll have him check out the ECM and grounds while he's at it.

Keep the suggestions coming, I need them....

GFR88IROCZ

notice you said you had pickup replaced, make sure the distributor was replaced correctly. not 1 tooth off which may account for timing problem.
DJ

kozman

the pick up coil is external, not in the dizzy, so i don't think that's the problem.

A few people mentioned the ECM, I have not replaced that but how would that effect my bucking and jerking problem?

Also, someone mentioned checking the grounds, I have no idea where they are, can someone direct me to the grounds.

snardos

The pickup coil is not external to the distributor. It is under the rotor inside the cap. You have to take the distributor apart to change it and it plugs into the ignition module.

GTA90X

iTrader: (2)

In regard to the ECM:If the ECM is not properly processing the inbound data from the the various sensors, the commands it sends to the injectors,etc. will not coincide with the current state of the engine.

Example: Engine is running at 185 degress. Coolant Temp Sensor sends signal to ECM. Due to an error the ECM thinks the CTS is reading 50 degress. ECM richens the mixture due to match the lower temp. Engine now running too rich for current conditions. This was just an example and wasn't meant to be specific to your situation. This could apply to many scenarios.

My advice would be to have the ECM properly checked. Not just a snapshot of the data at any one time either. It needs to be comprehensive. Also make sure that it is getting into "closed-loop". It runs in "open-loop" for the first couple minutes on order to "dial-in" all the proper values for the various sensors. Once it goes " closed loop" you should be running at "optimally" according to the ECM.

kozman

Snardos, mine looks like this

GTA90X

iTrader: (2)

thats an ignition coil. pick-up coil is in snardos post. completely different part and function.

kozman

my bad, I'm losing my mind with this car...

87350IROC

iTrader: (2)

Again, I will recommend replacing the ECM, it can fix a lot of strange problems. Also its cheap and really easy to replace.

Dale

iTrader: (12)

As for grounds. If one is loose, it will not allow the sensors to send data properly to the ecm. Or if the ecm has a loose ground, it cant process properly.

Ground locations. Start with your battery and follow its wires. Make sure there not corroded on each end. Then I think there is a ground on the back of one of the heads, or maybe one of the intake bolts. Just grab a section of the wireharness and start following it out and around looking. One under the dash for the ecm.(I dont have a stock harness so mine are in different spots then stock).


pickup coil IS inside the dizzy. The dizzy has to be removed and basically rebuilt to replace this part. Snardos is correct, that is the part. It is the whole key to the ignition system.

8T9 BANDIT

get a ecm.. there the same from 85-89, you just have to put youre chip in there. just maje sure its from a tpi car. 305 or 350, like i said, only the actual chip is different from motor to motor and yr to yr.

kozman

It looks like the problem was found...it's the Prom. Good news but bad news,the problem is the prom is discontinued !!!!. Back to square one.

I called several dealerships and they said the same thing...the prom was discontinued 6 months ago.

Any ideas where I can get a prom for an 89 T/A, 5.0, auto, 2.77 rear end?,

PLEASE HELP

Saigon_Bob

iTrader: (2)

As a mechanic I have to say, first find a new Prom... or ECM... the junkyards should have tons of them. Try calling LKQ (if theres one close to you).

Second after you R&R the ecm, replace your mechanic... he's a parts changer and obviously not doing anything for you except spending you money.

GTA90X

iTrader: (2)

Glad you got it figured out. Let us know how you do after replacing the PROM