Hot start issue, 89 IROC L98
 

Starts fine when cold but doesn't want to start after cutting the igniton then restarting when hot. Has anyone else had this issue? This is an 89 IROC-Z with a L98. Weak fuel pump maybe?

Re: Hot start issue, 89 IROC L98
 

I had the same issue with my iroc. It turned out I had 3 bad injectors. I replaced them with a set of bosch 3's from southbay and haven't had the problem since. If you still have the factory multi-tech injectors on the engine, you should ohm them to see if any are bad. I think a good reading should be around 16 ohms.

Does it turn over? If not. Does it have headers? Might be the starter getting to hot if your headers are too close.


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Re: Hot start issue, 89 IROC L98
 

The car turns over fine, don't have headers yet, but it hits a couple of times then does nothing. And this is a sporadic issue... also the car runs rough at idle, shakes and sputters... but smooths out once you start driving. The previous owner changed the plugs, wires and installed a new distributor and all new sensors. Could this be a fuel injector issue? It seems down on power too... and the car only has 60,000 miles. One thing I noticed is the passenger side exhaust manifold is leaking but I don't think it would cause such a starting problem or rough idle.

What should I look for?

Also, when checking the fuel injectors... you just remove the plug and read ohms between the two terminals on the injector correct?

Re: Hot start issue, 89 IROC L98
 

Thanks,

What color is your car? This IROC is a metallic candy red color and I've never seen one before. I absolutely love the color... yours looks the same but I can't tell. Nice car btw!

Re: Hot start issue, 89 IROC L98
 

When checking the injectors, yeah, you just unplug the injector and measure the ohms across the 2 terminals on the injector. Do 2 readings, 1 while its cold and the other while its hot. That way you can see if there is a change in resistance. Injectors can have a good reading cold but a bad reading while they're hot or vice versa. The color of my iroc is called flame red metallic. Its a darker red from the bright red available on our cars. I see more bright red Camaro's than the dark red ones.

Re: Hot start issue, 89 IROC L98
 

It is well worth the money to get a set of bosch 3's from south bay even though your injectors ohm out fine. i changed mine out a couple weeks ago and gained 4 mpg on the highway. starts and runs better too. oh and my old multec injectors ohmed out at 15-16 IIRC

Re: Hot start issue, 89 IROC L98
 

I ordered a set from South bay yesterday actually, and I'm glad I did. Tested all eight injectors today and definitely had some bad ones. I had one read .9 ohms, 11 ohms, 13 ohms, 11 ohms and the rest were around 16 ohms.

Out of curiosity, the one that read .9, is it working at all? Wondering if that cylinder is dead from no fuel. The car feels sluggish, especially at idle or when revving. It cruises fine but is really hard to start and idles rough. Usually have to hit it with a can of ether to crank it up.

Re: Hot start issue, 89 IROC L98
 

Unplug it while the car is running..You'll be able to tell if it's working.

Re: Hot start issue, 89 IROC L98
 

Installed some new 22 lb injectors from South Bay. Car runs great now. Thanks for the help

Re: Hot start issue, 89 IROC L98
 

Glad you got it fixed. Its a whole different car when it running right. When I installed mine, the engine ran the best it ever had since owning it. Happy that we could help.

Re: Hot start issue, 89 IROC L98
 

Got another problem with this POS now... So I installed new injectors, ended up breaking a bolt off on the thermostat housing so I swapped intake manifolds. Car ran great... noticed oil dripping on the ground after driving it for an hour or so. The intake was leaking oil between the block and intake on the rear, so evidently I didn't put a large enough bead of silicone on it. So I pulled the car back in the garage, tear it all back apart. Now that its back together the damn thing won't start. It'll turn over, fuel pump comes on and injectors tick but no spark. I even tried starting fluid to make sure.

Everything is hooked up correctly... so I'm stumped. The distributor is brand new, new plugs, wires and coil. So what else should I look for? And of course my multimeter doesn't work either. What a day...

Re: Hot start issue, 89 IROC L98
 

Hmm, a fuse perhaps? it sounds like no spark or incorrect dizzy placement, although i would think it would at least run terrible with the dizzy in the wrong spot... :huh:

Re: Hot start issue, 89 IROC L98
 

does your SES light come one when you turn the key to ACC mode?

Re: Hot start issue, 89 IROC L98
 

Is it supposed to or not supposed to?

Re: Hot start issue, 89 IROC L98
 

One of the terminals on the ignition module was bent. So it's fixed thankfully. Now the car surges at idle, not sure what is causing it to do that. Something out of adjustment maybe?

Re: Hot start issue, 89 IROC L98
 

First thing would be a minimum air and tps adjustment. If that doesn't get it (like mine) take off the throttle body and clean it really well with brake cleaner. Be sure to take off the iac housing off of the bottom and clean that. Glad it actually starts now!

Re: Hot start issue, 89 IROC L98
 

Awesome, thanks for the tip! I'm pleased with how well the car is running. That 350 is a strong motor, more so than I expected. Having gone from an LS1 to a L98 anyway, the torque is impressive. Just wish it had more up top but I plan on switching to a mini ram intake so that sure cure the lack of pull in the upper RPM's.

I'll adjust the TPS and see what happens. Thanks again...

Re: Hot start issue, 89 IROC L98
 

its supposed to. Good to hear its working. now just do what soldier did and check the timing also

Re: Hot start issue, 89 IROC L98
 

Here is my project, real good shape for a 89...

Re: Hot start issue, 89 IROC L98
 

you went from LS1 to L98?! :eek: whyyyyy?

Re: Hot start issue, 89 IROC L98
 

Personal preference mainly... I love the LS1 motor but hate the 4th gen body and interior. I'm actually doing a LS1 swap into my other 89 IROC-Z so it didn't bother me to trade. This car is much nicer than the 98 I traded. Guess I just like these cars more.

Re: Hot start issue, 89 IROC L98
 

Oh ok I thought you swapped out an ls1. I think you would be the first in history. Ls1 and third gen is perfect combo

Re: Hot start issue, 89 IROC L98
 

Ha ha, yeah my friends thought I was crazy trading a LS1 4th gen for another L98 IROC-Z. But since I was doing the swap in my other IROC it didn't bother me to do the trade. My girlfriend hated the hump in the passenger side floor board on that 98, it put her knees in the dash. She is tall and long legged so the third gens are more comfortable, as they are for me too. But yeah I agree, a third gens looks and handling with a LS1 is the perfect combo... for sure.