bowtiesandbirds

Hello, I am new to the site.

Here is the problem: 1989 IROC 350 TPI, the car does not want to start cold.
Sometimes it will start after cranking for a long time, sometimes not. If you shoot some propane into the intake it fires up and runs. Runs fine after it starts until you shut it off then sometimes it fires right up, sometimes you have to sit and crank it.

ROCFATHER

Sounds like a fuel problem. I'm thinking fuel injectors.. fuel pump. Have a professional check it out. Mine was the oppostie would not start when hot.

bowtiesandbirds

My fiancee was stuck in Florida with the car and had it to three different shops. The fuel pump, pump reley & oil pressure switch have been replaced.
The injectors have been removed cleaned and checked. I replaced the fuel filter just to eleminate that. I checked the spark, seems to be good. I unhooked the fuel lines at the engine and fuel is flowing threw the system.
I don't have a guage to check the pressure though. The regulator seems like the only major part left. I'm sure the shops would have checked that though.

Any ideas?

TMZIrocZ350

I would say check the fuel pressure regulator as well as the IAC valve. If the IAC is stuck closed then it will have a hard time idling.

bowtiesandbirds

What is the IAC valve? The car idles fine once it is started.

It is like the car is trying to build up fuel pressure but having a hard time getting enough pressure to make the injectors work.

I guess I will have to breakdown and buy a fuel pressure gauge or take the car someplace.

TMZIrocZ350

IAC is the idle air control valve. It is on the bottom of the throttle body and acts like a choke on the car. It closes on start up and then opens back up when the car idles. If the car idles fine then this probably isn't the issue. Checking fuel pressure is a very good start.

bowtiesandbirds

Could the IAC not be closing when starting the car (not choking the car enough to start)? Is there a way to test if is working right or not?

bowtiesandbirds

Hello, is there anybody out there?

TMZIrocZ350

Run a test on the IAC vave and also check the TPS voltage. They have a good tech article on how to do this right here on this site.
https://www.thirdgen.org/tpimod2

bowtiesandbirds

I checked the fuel pressure valve by just pushing it in. When the car is running it squirts out pretty good. When I check it with just the key on after the pump primes and stops it just dribbles out.
Is that normal or part of the problem?

The IAC article just shows how to adjust it at idle. The car ides fine once it is started.

I haven't checked the TPS yet.

dmanella

Hello,

I am new here to and have the same problem but a 1987 350 but only at hot.

I did not replace any of the above that you mentioned but I have several thoughts as to what it could be.

Because I am married I can't spend any money on it but here are some things.

The not holding pressure when the key is off is usally due to the pulsator in the fuel tank which holds the pressure on the return line. Did they replaced the Pump, filter or (sock) in the tank and the pulsator?

Another common problem with these cars is EGR valve as well. This is located under the plemuim.

Also a common issue is the reluctor in the distributor and the pickup coil in the distributor.

How many miles are on the car?

Daryl

bowtiesandbirds

The clock says 72,000 miles on the car.

The fuel pump was just replaced but I was not there to see what they did or did not replace other than that.

It is getting spark but there could be some other issue with the distributer on startup.

That the weird thing, once it starts it is fine and can be driven forever until you shut it off. Then if you are lucky it starts again if not you just sit there and crank it.

When it does start. You crank for awhile and it will hit a little here and there.
It just starts hitting more and more until the car finally starts.

dmanella

My car does the exact same thing. I just do I quick crack of the starter and it usally works the best.

They should replace everything when they are in there. When running my pressure is at a 43.5 adjustable pressure for my injectors but you should get a pressure gauge on the fuel rail to see if it is holding at all. My has been diagnosed as a pulsator problem but when I get the money I will change all of the fuel pump system.

On my car I am going to change the distributor first it is easier and my car has 120,000 mile on it so it is due.

Daryl

bowtiesandbirds

I just looked through the bag of parts the mechanic gave my fiancee after they did the "work".

Fuel pump & sock. No pulsator. I'll bet that is it. It is the only thing that really makes sence. All the mechanics thought the fuel pressure was bleeding off but didn't know why.

dmanella

There are other things that will cause a bleed on the fuel pressure you must check all the variables.

Here are some.

Leaky fuel injectors, faulty fuel pressure regulator.

I have a shop manual at home if I can I will scan the procedure for you but you really need a pressure gauge.

I can only go by memory at this point but the procedure is to connect fuel pressure gauge. Turn ignition key on pressure should read 40.5-47 PSI and hold. If not holding turn the key off pinch with vise grips the inlet fuel line hoses rubber flex line located near the brake master cylinder. The inlet is the larger one looking at the front of the fuel rail and follow to the flex hoses pinch off and turn the key on if pressure holds then there is a problem with the Fuel Pump, Pulsator or fuel pump pressure valve. If pressure falls then it is one of the injectors or fuel pressure regulator. Next pinch off the return line if pressure holds then it is definatly the pulsator.

I will verify tommorow with my shop manual. But I am pretty sure this is the procedure.

Daryl

bowtiesandbirds

Thanks for the help....

I don't have a gauge and can't really afford to buy one right now. I will see if I can get ahold of one though.

The injectors have been cleaned and checked so they should be working. So it sounds like that would leave the regulator or pulsator as the most likely faults.

dmanella

Yeah it looks like it at least thats what it is with my car.

Here is a quick link I found online. check it out. http://www.mightyautoparts.com/pdf/articles/otl0398.pdf

Thanks Daryl

'89 Iroc

Bowtie I am having the same problem. Car runs fine after starting, but it wont start unless I spray a little starting fluid into it. A few months ago the problem was hit and miss but now it's everytime I try to start it. Has anybody found the problem yet?

'89 iroc 350 5.7tpi

dmanella

Hello 89 Iroc,

No I won't be finding my problem anytime soon no Money,

Been dealing with this problem for 3-4 years now.

look at the common problems I listed above these all cause a hard start and the EGR valve will cause a rough idle and hard to start condition.

Daryl

'89 Iroc

The car runs like a gem after I get it started. But most the time, if I shut it off, I am back to the starting fluid. And It dont matter if the engine is warm or cold still the same. Fuel pressure is holding for a few minutes before it starts to bleed down so I dont think fuel is the problem.

Anybody got a diagram of the vacuum lines?

Frustrated owner,
Tony

dmanella

Hello Tony,

How much doe's the pressure drop and how long does it take. If you turn the key on and have the pump come on the pressure should stay between 40.5 and 47 PSI if it drops any more than this then follow the steps above I just did it on my car and it is definatly something in the fuel tank for my car.

If you crank and crank and crank the car will never start. Just turn the key on you will here the fuel pump relay click on which will prime the injectors. Turn the key just quick hit don't hold it. Keep doing this and it may take three to five trys but it is better than pulling out the starting fluid and spraying it in there I have been doing this for several weeks now and have not had to use the starter fluid once since I started doing this.

Daryl

dmanella

I have solve this problem with hard start hot and cold. I replaced the distributor.

Daryl

'89 Iroc

Thanks Daryl, I will see if it fixes mine. I haven't drove the car 10 times in the last year because It was so unreliable to start.

Badass19905.7

Hey guys im haveing a similar problem...
I have a 1990 iroc z 350
When i go to work in the morning it always takes me about 7 trys to get the camaro to start up i ususally let the fuel pump prime with my foot on the gas it seems to help it start. When the car heats up it runs great and fires right up. But after it cools down it starts all over again. I can smell fuel every once and awhile too. I dont know how to really check for anything either. I just bought the car. The owner said the fuel injectors run hot pn the car idk what exactly that means? Please someone help! Also when i brake to a stop i hear a banging noise er maybe a back fire? Also twise when i started it up i pressed down the pedal to the floor and had no power and went nowhere then the iroc died. HELP!~!~~!!!!

Badass19905.7

help!!!

PLEASE!!!!!!!!

'89 Iroc

I've read post about cold start injectors. Do a search on that and see if that helps. Sorry I cant be more help

DBLTKE

iTrader: (1)

any updates?

'89 Iroc

I still have the problem, but I have a work around that i read in an earlier post. All you do is turn the switch on and let the fuel pump prime 2-3 seconds. then just bump the the starter over. I don't know why this works but it always starts this way. Just make sure you bump the starter over, if you do more it will never start. I hope that helps.

JC316

Had the same problem with my 89 Iroc 5.7L, turned out to be several bad fuel injectors.

dmanella

Hello, I had this same problem. I replaced the distributor and it fixed it. Now I have a new problem that is fuel related. My car bucks after the fuel goes down past 3/4 of a tank. This could be one of two issues. One is the evap emissions not letting the fuel tank release pressure or the in tank fuel pump, filter, pulsator, and sending unit. I will post next spring when I replace my fuel pump, pulsator, and sending unit/filter. This I am sure is what my new problem is because I replaced the distributor plugs and wires.

quisterio

My GTA was doing the exact same thing, and now it's sitting in a dealership's service garage having its fuel pump replaced

z man

i have a double problem my 89 iroc 5.0 wont start when hot or cold,unless i shoot it up with starter fluid then it runs but misses i just replaced the pump,distribuitor,regulator,and fuel filter.at first i put two part house fuel pumps in it and they wouldnt get enough pressure to the rail at all,so i ordered one,a high pressure pump and now it will idle when at first it wouldnt do nothing,any ideas, cause im about to give up

JC316

Fuel injectors. That is what it was on mine. I would recommend changing them out.

dmanella

Bad Fuel injectors fixed hot start issue and fuel pump fixed cold start issue.

Hope this helps