'91 740 No Hot Start Until Charge Applied

Post by **jimmy57** » 03 Feb 2011, 21:33

I'm a little confused. I get from some of the posts that it is turning over slow and from some of the others I'm left with the idea of cranks over well but just doesn't start. Which is it?

If it is slow cranking speed then I might suggest removing the starter and then removing the end cover and dumping out the brush dust from the brushes wearing.
I have had several of the Bosch gear reduction starters like that car uses that get inconsistently slow to crank engine over. I took one apart instead of changing it and the end cover for motor was caked with black and copper dust clumped up by the grease used on bushing. I cleaned the motor out and put it back together and it was fine. Brushes had lots of life left in spite of the fact there was so much brush dust inside.

SkyVolvo · Post by **SkyVolvo** » 03 Feb 2011, 22:52

I'm just as confused - there are times when it seems to turn over slowly, but does start, and other times when it cranks well but doesn't start. I'm going to revisit and retest the battery much more thoroughly.

It doesn't give any typical signs of battery issues - all lights come on, headlights look fine, etc. - and really, for the most part, it does sound like it's cranking strong. I let the car sit for about three days in 0 degree weather without driving it, and when I turned the key on Monday it started just fine - a good, strong start. But if it ever refuses to start, all it takes is a quick boost from another car. Is this maybe a starter going bad? It's not screeching or making any unusual sounds.

SkyVolvo · Post by **SkyVolvo** » 04 Feb 2011, 15:44

We have a solution, hopefully:

I had AutoZone retest the battery today. The first test showed a faulty battery, the second showed good results, and another test pronounced the battery to be at the end of its useful life. Their test results mirror the unpredictability of my own issues with it - seemingly fine one day, faulty they next. The testing-person guessed it probably had a bad cell, as it was less than two years old, and they gave me a free replacement under warranty.

If the battery was indeed the culprit, my only guess for some of the symptoms was that it was JUST under the useful voltage/amperage at times, producing what sounded like successful cranks but were, in fact, sub-par. If the problems return, I'll continue the thread, but otherwise, we'll consider it closed. Thanks for all the suggestions - if I had tried to get a more thorough test from AZ the first time they looked at it, maybe I could have saved you all the trouble.

Post by **billofdurham** » 05 Feb 2011, 11:54

Thank you for the update.

Bill.

SkyVolvo · Post by **SkyVolvo** » 25 Mar 2011, 01:31

I felt I should go ahead and add this: on top of having potential battery issues, I found out that I was, in fact, definitely having problems with my radio suppression relay. When it was acting up again after the battery change, I switched the relays once more and it started right up. I ordered a new relay from FCP and stuck it in my glove box, which was great, because within a few days the old fan relay also failed. I popped the new one in and have had no starting troubles whatsoever - now I just need to get another relay for my fan.

memasarif · Post by **memasarif** » 26 Mar 2011, 13:09

I have a similar problem. My 1994 Volvo 960 would not start until the engine completely cool down. I do not get any codes. I replaced the starter, rnp switch but it did not work. Once the engine is cool it starts without any problems but even if you turnthe engine off after 10 seconds it wont start for another two hours. What I noticed is when I jump the car unlikely yours after 10 seconds cranking it starts but then after 5-8 seconds engine stalls. Let me know what you got.
Thank you.

DBULL · Post by **DBULL** » 27 Mar 2011, 16:17

As a tech I ran into this several times.You need to check the battery voltage WHILE CRANKING THE ENGINE.When the voltage falls below a certain point(8v I think) the computer will fail to respond.I have seen straight shift cars that would start by being rolled off but not with the starter since there is no voltage drop(drain) from from the cranking.When you jumped the car you simply raised the battery voltage to where the modules would kick in.DBULL

DBULL · Post by **DBULL** » 30 Mar 2011, 14:48

Another werid intermittent no-start that I ran into was a 740 turbo which turned to be the turbo itself.It would occasionally stop at a certain spot and completely block the exhaust.By simply pulling the intake hose and turning the spool it would fire right up.DBULL

'91 740 No Hot Start Until Charge Applied

Re: '91 740 No Hot Start Until Charge Applied