Slow start and surging
Thread Starter
8th Gear
Joined: Nov 2012
Posts: 8
Likes: 0
Slow start and surging
My 89 C4 (350 L98) has just recently started surging while driving and then when I turn engine off, it is difficult to start again until it cools down. The surging and the starting problem seem to be more prominent after engine warms to operating temperature. The engine starts quickly and runs great when cold. It willl start when hot if I use a squirt of starting fluid, but surges badly. I have looked into possible problems with back pressure from catalytic converter and have changed the inline fuel filter as well. Any ideas or similar experiences? Any answers to solve these issues? Thanks.
Last edited by myred89vette; Nov 24, 2012 at 10:47 AM.
Race Director
Joined: Dec 2006
Posts: 10,383
Likes: 4
When it is hard to start check for what's missing. Do you have spark? do you have fuel?
I would want to check the resistance pole to pole on the injectors. I would also suspect the coil and icm since it seems heat related.
I would want to check the resistance pole to pole on the injectors. I would also suspect the coil and icm since it seems heat related.
Burning Brakes
Joined: Mar 2012
Posts: 769
Likes: 22
From: California
FL Events Coordinator
St. Jude Donor'13
I had surging about a week ago on an 89 corvette and it ended up being a vacuum leak near the throttle body or at the other end of a line going to the throttle body. I used a helpful diagram and since all the lines were original I replaced them all and replaced the plastic tubing going from the MAF sensor to the throttle body so it would be new also and air tight and not have any air slipping in from there also.
With all that it did fix my surging issue and ran A LOT better.
~Stephen
With all that it did fix my surging issue and ran A LOT better.
~Stephen
Thread Starter
8th Gear
Joined: Nov 2012
Posts: 8
Likes: 0
I can shoot a squirt of starting fluid into it when it is hot and won't start, and it will fire and run. although it still surges. Thanks for the input. It gives me a starting point. The car had been running fantastically until it started this.
Race Director
Joined: Dec 2000
Posts: 17,551
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From: El Paso Texas
How many lbs of fuel pressure during a no-start event? If it's low only when hot, it's likely the fuel pump is on its way out. Worn fuel pumps will often work fine cold, but when heat and resistance builds up, they falter.
Heat related no-starts are typically ignition related, but if it fires only on starting fluid when hot, this is fuel delivery related. I also want to know the resistance on each injector during a no-start event.
Heat related no-starts are typically ignition related, but if it fires only on starting fluid when hot, this is fuel delivery related. I also want to know the resistance on each injector during a no-start event.
