I just bought a 89 and read that the injectors can be the cause. I did the ohm test I had two under 12 ohms and two more under 9. I just ordered 8 if that dont fix it what else could do this? I already did a normal tune up the owner prior to me did not look like he did any maint.

 

Who did you get the injectors from?

Jim

 

Our 87' had a similiar problem. It would start fine cold, but was real reluctant to start when hot. The problem was a bad fuel regulator. There is a diaphragm that 'holds' the fuel in the rails after shut-off and if it is bad, it causes the fuel to leak back to the gas tank until it is empty and then you have to wait until the whole thing is repressurized under start up.

It is on the back of the intake manifold on the passenger side under the air box. Our mechanic showed me how to test it using a fuel pressure gauge on the schrader valve. You'd have full pressure right after shut off, but then you could see the pressure dropping steadily down as the diaphragm leaked back.

 

Better yet:

http://chevythunder.com/fuel%20injec...g%20pg%20D.htm

No Start or extended start, fuel system problems: If the electrical system checks out, and you are still having problems getting the vehicle started, we'll look at the fuel system. Low pressure and no cold start enrichment are two common problems we'll look at.

This is where you will need a fuel pressure gauge. The most common problems of fuel pressure is a ruptured fuel regulator diaphragm, fuel pump check valve not holding, loose or leaking connections, leaking injectors. Locate the fuel gauge connection valve on the rear right side of fuel rail near regulator. Wrap a shop rag around the connector, while installing the pressure gauge, to absorb any leakage. When you turn the ignition key on, and the system pressures up, see that you have 40-47 psi in the system. You may have to cycle the key more than once to obtain maximum pressure. A slight drop of a couple of pounds over a minute is considered normal. Start the engine and note pressure, it will be 3-10 lbs. lower with engine running. If it is not, you'll have to use your hand vacuum pump and attach it to the fuel pressure regulator vacuum line. Apply around 10" of vacuum, the pressure should drop by 3-10 lbs. If it does not, you'll have to replace the regulator diaphragm

 

Checking fuel pressure under a no-start condition is the best place to start troubleshooting. Guages are $20 at Harbor Freight tools, or you can borrow one from AutoZone under the tool rental program.

 

You can see both the schrader valve and the fuel pressure regulator on the upper left. I believe you can just replace the diaphragm, though how you get in there with the fuel runners and airbox is beyond me (the mechanic did it), though I did the rebuild on the top end. Possibly a short screwdriver or angle driver?

 

I just got the car last week and just ordered injectors today after reading out the injectors.

 

From all of my research I have found many things that can cause a no start situation after warm up. Seems most are always fuel related though. Injectors, reg or fuel pump. if they quit loading me up at work I'll do some more research for you.

get a gauge on it and report back to the smart guys!!

 

I think the manual says to take the runners off but I read somewhere someone sy you can replace it with taking the runners off. It also said to take the fuel rail off.

 

Well I changed the injectors and is running and starting like adverstized.

 

Thanks for getting back to us. And congrats on another success story.

Out of curiosity, did you replace the rgeulator? You might as well have since you were in there anyway and they seem to act up a lot.

Never seen so many problems with fuel regulators like on these things in my life.

I will be replacing my injectors and reg this weekend. That is if the injectors come in and the parts store gives me the correct regulator. I have been bitten by Murphy's law lately it seems on those two fronts.

 

No I did not replace the regulator I probrably should have but I was just work the issue at hand that would have been my next thing. That TPI is a pian the first time but am a exprt now.

 

Also I got the injectors from an online store for 175 shiped for 8. They are working for me and that is 60 percent cheaper. I will post the name when I get home.

 

For startup, the ECM pulses the injectors based on Coolant Temp - you scan it to find out what the ECM is seeing from the Coolant Temp Sensor. If it's the wrong temp (equal to or +/- maybe 5 degrees from your dash display would be ok), it's getting too much or too little fuel.

Too little or too much fuel at all times - volume/pressure - would effect driveability; not just start up. BUT, flush the system before you install your new injectors by disconnecting the filter and putting a hose on the line. Put the other end of the hose in coffee can and turn on the key. That should spit out whatever is in the line. Put in a new filter and repeat at the rail before you reattach the inlet.