Engine cutting out

[khargis]

Hello folks, so I went through all the procedures with the battery posts and clamps (cleaned and scraped), pulled off all the connections to the starter post on solenoid (cleaned and scraped) red and white large wire next to battery positive wire, put back and tightened, removed nut holding starter ground on solenoid, removed ground connector (cleaned and scraped) and found the 2nd (rear?) nut loose and the post was loose, tightened and put back together. Bus started up this morning, but the starter/ solenoid still sounds weird (and seems to lack starting power) and keeps spinning even when the engine is running and I have to tap on solenoid to get it to stop spinning and then I drive fine.. kind of, I took for a test drive a bit ago and this happened once; I accelerated and lost acceleration power for a second? Is this related to starter/solenoid issue? I am still going to take the bus in where I purchased the rebuilt Bosch starter and have tested to get a new one put in if tests faulty. The thing is I don't really trust in the competency of the mechanic that put it in due to the lack of tightening the solenoid starter ground bolt. Is this reasonable? If anyone has any suggestions, I would greatly appreciate the feedback. Kris

[Amskeptic]

Hello folks, so I went through all the procedures with the battery posts and clamps (cleaned and scraped), pulled off all the connections to the starter post on solenoid (cleaned and scraped) red and white large wire next to battery positive wire, put back and tightened, removed nut holding starter ground on solenoid, removed ground connector (cleaned and scraped) and found the 2nd (rear?) nut loose and the post was loose, tightened and put back together. Bus started up this morning, but the starter/ solenoid still sounds weird (and seems to lack starting power) and keeps spinning even when the engine is running and I have to tap on solenoid to get it to stop spinning and then I drive fine.. kind of, I took for a test drive a bit ago and this happened once; I accelerated and lost acceleration power for a second? Is this related to starter/solenoid issue? I am still going to take the bus in where I purchased the rebuilt Bosch starter and have tested to get a new one put in if tests faulty. The thing is I don't really trust in the competency of the mechanic that put it in due to the lack of tightening the solenoid starter ground bolt. Is this reasonable? If anyone has any suggestions, I would greatly appreciate the feedback. Kris

If the starter is running on, it is definitely defective. It needs to have a new bushing installed in the bell housing too.
Lost power does not really relate to a starter unless it is pulling severe current from the battery and annoys the fuel injection. You would hear holy hell back there if the starter was doing that while under way.
Colin

[khargis]

Is it possible that the loss of power would be the afm, due to the scratched surface? It was running great after you left, so I feel like the problems are related as they happened in conjunction with one another. I will get the starter replaced and ask about the bushing in the bell house, thanks Colin.

[Amskeptic]

Is it possible that the loss of power would be the afm, due to the scratched surface?

Totally. That was our priority effort on appointment day, remember all the phone calls? I gave you a week on that poor thing.
Colin

[khargis]

Heard!

[Jivermo]

I've been following this, and I'll suggest something here. I had a continuing problem with my '78 bucking and cutting out at certain times. It was driving me nuts. After going through a whole bunch of stuff that I won't bore you here with, I decided to take a look at the double relay. When I went to take it off the firewall, the brown ground wire that was attached with the mounting screw popped out from behind it. Over time, it had become loose and was lodged behind the double relay-making intermittent contact. The fuel pump was turning on and off with the loss of power. I put a new terminal on, cleaned all contact surfaces, and made a tight new connection. End of problem. Finally.

[Amskeptic]

I've been following this, and I'll suggest something here. I had a continuing problem with my '78 bucking and cutting out at certain times. It was driving me nuts. After going through a whole bunch of stuff that I won't bore you here with, I decided to take a look at the double relay. When I went to take it off the firewall, the brown ground wire that was attached with the mounting screw popped out from behind it. Over time, it had become loose and was lodged behind the double relay-making intermittent contact. The fuel pump was turning on and off with the loss of power. I put a new terminal on, cleaned all contact surfaces, and made a tight new connection. End of problem. Finally.

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Re: Engine cutting out
Postby Amskeptic » Sat Dec 29, 2012 12:10 pm
satchmo wrote:So far, worsening problem.

Worsening should help you find it.
Imagine, what kind of problem could have actually survived all that you have already dealt with?
Loose double relay ground? Cracked spade on the engine block ground cluster? Slightly out-of-position wire terminal in the double relay connector?
Colin

Terminals that get shoved out of the molex block in various connectors can be fiendish to find. A prominent example is the AFM plug which often gets a lot of action.
Colin

[Gypsie]

regarding connections:Someone just recently made mention of a "number of times" a multi plug can be pulled apart and put together and maintain a fully spec'd connection. Not certain of any particular numbers but it made me think of how long these components have been in play and the potential numbers of times the connections are handled. I'm sure many have gone over their number. Periodic spray cleaning may help.

Also I think that heat cool cycles to connections in the engine bay area (coil connections etc) has an effect on the metalurgy of, primarily, the female connection. I have had those snap with finger squeezing to tighten the fit. I can imagine a circumstance where a connection losens during a heat cycle and causes all manner of tail chasing...Swapping out some of those connections after, say, 30/40 years might help some.

[Amskeptic]

regarding connections:Someone just recently made mention of a "number of times" a multi plug can be pulled apart and put together and maintain a fully spec'd connection. Not certain of any particular numbers but it made me think of how long these components have been in play and the potential numbers of times the connections are handled. I'm sure many have gone over their number. Periodic spray cleaning may help.

Also I think that heat cool cycles to connections in the engine bay area (coil connections etc) has an effect on the metalurgy of, primarily, the female connection. I have had those snap with finger squeezing to tighten the fit. I can imagine a circumstance where a connection losens during a heat cycle and causes all manner of tail chasing...Swapping out some of those connections after, say, 30/40 years might help some.

I just ran into one in Bluff UT, a broken wire inside the CSV plug, all hidden by the boot. At first glance everything looked good. The second most subtle failure that is easy to overlook is the terminal that has been pushed inside the connector and does not meet its pin when plugged in. The most subtle failure has to be that stupid broken wire hiding under the rubber boot nestled amongst the others that are still good. All the terminal fingers will look perfect.
Colin

[Lanval]

Colin,

Remember all our craziness with the AFM on the rat van? Only to discover (only Colin could discover this) that some earlier SOB had removed one of the wires from the AFM connection? And we had to solder a new one back in?

Attn: All IAC fanatics. You cannot. CANNOT! check your connections thoroughly enough.

That is all.