Laborious crank on hot starts

[Canyonero]

I've experienced this for a long time on my 2.8 and on the 3.4, on a hot start the engine cranks very slowly (for a couple revolutions?) and either fires or starts cranking faster and fires. Most notable if I stall the truck and try to restart, but it will even do it if I stop to get a cup of coffee and then restart.

I've dealt with this a long time, but recently I had my battery cable (from the rear mounted battery, optima red) come lose and short on my exhaust which was a bad situation since I didn't have protection. I installed a 250amp circuit breaker which cold-starts the truck just fine. But on these laborious cranks I will trip the circuit breaker more often than I'm comfortable with. Not cool, especially if you stall in a bridge toll both... Not only will I trip the breaker, but the breaker needs to cool down before it will reset.

That's not the issue I'm trying to solve though. Why does this thing crank so slow and what can be done to resolve it? Is there a more powerful starter, or a gear reduction starter than can be used on a left-hand mount like the Troopers/Fieros have?

I'm going to swap my alternator bracket so I can regain the clearance to put my battery back in the engine bay so that won't have to use the breaker (and regain my cargo space).

[bszopi]

What size wiring do you have running from the back to the front? Where is your ground located? Is it a solid ground connection? Ground wire size?

[Canyonero]

I think it's 4 AWG, ground goes to the frame (mount for a cargo hook) in the back. I have the engine grounded to the frame and the body, better ground than it had originally.

Like I mentioned, it even did this on my old engine with a different starter and the battery still in the engine bay. But I didn't have the circuit breaker, which ends up being the real problem.

[95Grand-Am]

Have you checked the timing too much advance could make it crank hard also.

[geoffinbc]

That cable is a little on the small size. Technically it is large enough to handle the current, but ANY voltage drop for a starter is bad.

I have a similar setup but I have 1/0 Welding cable for the power and ground. Welding cable is also a very fine strand and has a very strong jacket.

And I would not bother with the gear reduction starter. I have one now from a FWD car and it does not seem to spin the engine fast enough to start the engine as easyily as the old starter.

[Canyonero]

Just got my friends 2.8 trooper going again. Same slow crank on hot starts. I just don't know what to think.

[gpse3400]

Get a new starter. This is a classic case.

[Canyonero]

My starter is new/refurbished when I did the 3.4 swap. Old one behaved the same on the 2.8L. Same with my friends 2.8L. His new starter seized after about a week and we had to swap in one from my parts truck (which again, behaves the same).

I'm thinking it might have something to do with advance ignition timing when hot like 95Grand-Am said.

It's only a REAL issue on my Trooper with the rear battery and circuit breaker. The slow crank is just a curiosity on my friend's Troopers because they always start.

[geoffinbc]

Well are you both using the same brand of starter? What are your batteries like? Try doing a jump start on your vehicle. With a second vehicle running you will get more voltage to the starter see if the condition changes you may narrow down the problem.

[bszopi]

Just because I'm at work with my voltage drop calculator open...

Assuming a 12v supply, 20ft distance and a 85A draw (max rating of #4 wire for continuous duty), with #4 wire, you are dropping out 1.1v by the time it gets to the starter. Since Geoff mentioned #1/0 wire, using the same values, you are only dropping out 0.4v, which will help out significantly.

[WrathOfSocrus]

I have a similar setup but I have 1/0 Welding cable for the power and ground.

I think that is a very important factor people neglect when remotely mounting a battery. While conductor size is very critical, conductor composition is also important. Even though the cross sectional area of the vehicle frame is far larger than any production copper wire it still has an inherent resistance to electron flow. Compound this resistance along with the voltage drop across the length of the power cable and it reduces voltage to the point where the starter must draw a significantly larger amount of amps to turn. Running a ground wire to the block from the battery as virtually all production cars have will not only ease the drain on the battery and strain on the starter, it also gives a better connection to the alternator and would relieve the problem with the breaker.

However . . . .

That's not the issue I'm trying to solve though. Why does this thing crank so slow and what can be done to resolve it?

The fact that the issue occurred before moving the battery, and the fact you have a friend with a similar problem says there is more to it than battery location. Perhaps both vehicles have bad grounds or bad/corroded battery connections but the fact that this thread is titled "Laborious crank on hot starts" would indicate it is a heat issue.

How close is the exhaust to the starter? It certainly wouldn't be the first time a car came from the factory with heat issues such as vapor lock or starter problems. I'm pretty sure places like Jeg's and Summit sell heat shields and blankets and such for starters. If it seems to have trouble with hot starts I would try and reduce the amount of heat the starter recieves when the engine is running. A little insulation around the exhaust and the starter would be a cheap and easy way to reduce temperatures.

[gpse3400]

I'd be cautious regardless. Not all rebuilds are perfect. I have had many rebuilt starters not operate as they should; it will drive you crazy.

[geoffinbc]

Yea on the trooper the starter and especially the solenoid for the starter it brutally close to the exhaust. The exhaust system does have a heat shield but it may be wise to add some exhaust wrap or something.

[Canyonero]

Yea on the trooper the starter and especially the solenoid for the starter it brutally close to the exhaust. The exhaust system does have a heat shield but it may be wise to add some exhaust wrap or something.

I don't have a heat shield anymore, custom exhaust manifold back. Could be part of the trouble. I don't think my battery cable is the cause of the problem, but does compound it.

I'll suffer it a little longer, haven't been driving the Trooper much lately anyway. I'm getting a 3.1L this next week I hope. Swap the intake and accessory brackets over to the 3.4L and then I'll be able to put the battery back in the engine bay. I'll try to get some wrap on the exhaust too.

[geoffinbc]

I used it on my pickup to stop some wire loom from melting and it worked great. It is a good product.