98 T4R won't start after engine is warm

[19963.4lsr5]

My 99 Runner turns on immediately. After driving and turned off, it will not start again until it's completely cooled down. When the key is in the "ON" position, the lights come on, but when turned completely to crank, nothing happens. The starter and starter relay have both been replaced but still same issue. The battery is also new and the posts are clean, no corrosion. Any ideas? Thanks.

The starter doesn't turn the engine over or the engine turns over but will not start hot?


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[tystaco]

I am watching this thread. I had similar issues with my 2000 but not quite as extreme...just had like 8-10 second crank times once hot...it is my wife's ride now so it doesn't really see a lot of use but I think I got rid of it by swapping the ignition coils...got a set of 3 off of Amazon for $50...had good reviews and have done well for a month...but if it comes back I am going to be watching the ECT now.

 

[diverscale]

it is not the fuel pump check valve, it would start eventually

Looks like a ground issue. For a cheap trial, try taking 10 or 8 gauge cheap wiring. Make good connexions with terminals and spices from grounds and connexions, those are cheap, not just some messed-up connexions. Connect one wire from battery negative to any good ground you can find on engine. Connect another wire from battery to body (or sand and clean existing ground) and another from engine to body.

If the problem stops or gets much better, you have grounding problems and you can bypass by making good new ground connexions with 4 gauge or 2 gauge wiring.

 

[tystaco]

it is not the fuel pump check valve, it would start eventually

Looks like a ground issue. For a cheap trial, try taking 10 or 8 gauge cheap wiring. Make good connexions with terminals and spices from grounds and connexions, those are cheap, not just some messed-up connexions. Connect one wire from battery negative to any good ground you can find on engine. Connect another wire from battery to body (or sand and clean existing ground) and another from engine to body.

If the problem stops or gets much better, you have grounding problems and you can bypass by making good new ground connexions with 4 gauge or 2 gauge wiring.

Can you explain why grounding would change between an engine being cold and hot?

 

[diverscale]

Can you explain why grounding would change between an engine being cold and hot?

not scientifically, but I know that when metal gets hot, grounds that are bad cause problems. Probably has a link to metal dilation and increased resistance when a conductor is heated.

 

[NCt4rgirl]

'98 T4R starts fine when cold but shuts down once reaching normal operating temp.

I'm troubleshooting my niece's '98 T4R. It starts, idles and runs fine from cold start but shuts down once reaching operating temp (>5 minutes) and will not restart until the engine cools back down. I've read all previous posts and they all seem to have the slightly different symptom of just not restarting after the driver shuts it off. This T4R shuts itself off and won't restart. To be clear, it turns over fine just won't restart. Any suggestions on where to start?

 

[davidch]

Due to my long background - 48 years - with motorcycle engines, I am inclined to think "tight valve" whenever I read or hear of an engine that's difficult to start when hot.

Motorcycle engines run tighter clearances, typically, than car engines, often only 0.002" on intake and exhaust. As such, it doesn't take much for a valve to be at 0 clearance. In which case it starts just fine, but goes to negative clearance - and loss of compression - as it heats up. I've solved lots of "won't start when hot" on small Hondas by merely adjusting the valves.

Now, the 3RZ-FE engine of 4-cylinder Gen 3s is known to have exhaust valves that go to 0 over time, ie > 100k on the odometer. This is far less likely, though not impossible, on the V6, which seems to have much more durable valves.

So, check valve clearances. Alternately, check compression when the engine is hot. Sadly, checking the left bank's valve clearances on the V6 requires some surgery to gain access. A compression check is far easier there.

 

[neokhz]

I had the same issue. On my it was the temperature control valve. It was throwing too much gas in it thinking that the temp was way cooler than it was and flooding it. About a $20 part and it has been fixed now for about 10k miles.

 

[ColoCherokees]

Just to add another possible solution to the original issue:

My '98 (with the 3.4, now at 207K miles) would start, idle and drive just fine when cold. My issue occurred when I restarted it while still warm, or during extended idling (long drive through waits or the never-ending school pick-up line) with occasional throttle bumps. The engine would stall/die when giving it gas or putting it into drive in those situations.

I put a can of BG44K in the gas tank, and the problem went away. After a few months (and me getting to know my 4Runner better), I noticed the problem "almost" coming back, so now I add a bottle of Techron concentrate at every oil change and haven't experienced the symptoms in several years.

I know this type of problem can have a number of different causes, but wanted to put my experience out there since it's an easy and cheap way to start before replacing parts.

 

[blaze17]

Have you tried holding the gas pedal down about half way while cranking?

 

[LittleCaesar]

There are a myriad of possibilities with a no crank hot start for an engine but for the 5vz I would start with checking the ECU Main fuse under the hood and go from there.