91 supra comp 351 pcm

[stevedeese]

starts great when cold, runs perfectly. however when you stop after a run it just turns over like it doesnt have any spark. if it cools completely down it will start again. could it be something in that pcm system? anyone else have this problem? thanks.

[gtbrault]

I think there have been quite a few posts by guys with similar issues - try searching for "hard starting" or "starting problems" or something and you should be able to get some decent information.
I had the issue where it would start fine when cold and then once I got on the river I would turn it off and try to restart and the starter would be turning too slowly - like the battery was almost dead. I replaced quite a bit of parts but the starter was probably the main culprit along with old brittle battery cables. - Take your cables off and bend them, if they sound like rice krispies you've got a problem, trust me, even if the outside of the cable,the insulation looks fine they could be corroded inside. I'm hoping to have all of my problems fixed by tomorrow evening and on the water by Wednesday.
Good luck

[91impulse]

Love the older supras. I have a 91 supra impulse. It's very similar to the comps. You guys got any pics?

[rludtke]

starts great when cold, runs perfectly. however when you stop after a run it just turns over like it doesn’t have any spark. if it cools completely down it will start again. could it be something in that pcm system? anyone else have this problem? thanks.

The hard starting when warm problem is likely due to the fuel vaporizing in the float bowl after shut-down. This condition is called vapor-lock. Open your engine cowl when it occurs, and try to determine if it feels excessively warm under the cowl. Check the exhaust manifolds to see if they are excessively hot to the touch.

Opening the throttle to full while cranking will allow the vaporized fuel to be drawn through the carburetor and replaced with fresh cold fuel, and the engine will eventually start. Be ready to pull the throttle lever back when the engine catches.

The condition is caused by excessive under-cowl temperatures due most likely from the exhaust manifolds being hotter than desired. This is probably due to poor performance of the raw water pump impellor, which feeds cooling water to the exhaust manifolds.

The solution is replacing the impellor, insuring that the raw water supply isn't blocked, and also making sure no obstructions exist in the hoses and passages down stream of the raw water pump.

Adding an insulator between the engine and the carburetor will reduce the direct transfer of heat from the engine, making the carb less sensitive to vapor lock. This will not completely eliminate the problem however, especially if your exhaust is overheating.

[Adam10705]

your ignition coil could be bad. When they are going bad once they get hot they will stop sparking, your local autoparts store should have one be sure to get the right one if you have a points system or a electronic system will depend if you need one for use with an external resistor or not.

[SUPRALUVIN]

Ignition coil is going...skidim replacement...68$ delivery 2-3 days

[SUPRALUVIN]

Make sure you get a 1.5OHM coil...for use with external resistor. My guess is this is what you have in your boat.

[hawksfan]

I have had similar issues with my 99 legacy. My engine didnt crank when hot just heard the dreaded Tik tik tik sound. Did crank when I test next day hooked to water hose. Would also be an iqnition coil issue.

Thanks

[Memmer99]

stevedeese, I had the same issue last year. I upgraded to electronic ignition and a new coil and the problem went away.


hawksfan, The tik tik sound you're refuring to is more likely a starter or starter soloniod issue. Take it out and have it tested at your local auto parts store.