I have a 302 EFI in my 1985 F150 that I just purchased today. I have very basic automotive troubleshooting knowledge.

When the truck was driven to my driveway after a 20min trip, we made the deal and the seller left. After the seller left I went to move the truck but it was very slow to start almost as if the battery was dead. The battery, alternator, starter relay and voltage regulator are obviously very recent replacements. When we made the deal for the truck I was well aware that it had its problems (oil leaks all over, unknown true miles, driveshaft carrier bearing hanging by a string literally) but the hard start was not mentioned.

I have no clue at the moment but I will definitely check the battery. When I was shown the truck at my job it had been sitting for the whole 8 hrs and started right up. My Father-In-Law thinks its either from the engine getting too hot or the engine being worn out. (He's a little less than optimistic about the truck)

Has anyone else experienced this problem and where would be the best place to start. I would like it to be an electrical problem but would not be surprised if it is worse.

Thanks in advance

Mike

 

replace the short cable from the battery to the starter solonoid , its probably corroded inside and also replace the ground cable , those are the cheap fixes that i do first. after that its more spendy, ive seen more starters, solonoides , etc etc, replaced , when it was actually a high resistance cable due to corrosion, bob

 

Thats the kind of easy start I was looking for. I took a look at the battery again this evening and the wire could be part of the problem, not sure where the prev owner got them but the positive wire is almost three feet long and just coiled up behind the battery, not to mention one of the worst jobs of attaching the terminals to the end of the cable.

The grounds seem to be ok as suprisingly the engine bay is very rust free unlike the rest of the truck. Also while fiddeling around i discovered a great many disconnected wires and a 5 amp fuse in place of a 10amp for the inside lights. The electrical condition of this truck is starting to scare me lol.

I will see if any of this helps tomorrow

Thanks

Mike

 

It could also be the starter. After a while driving my 84 (302) and stopping for gas(for example), when I tried to start it again it would crank really slow for a while, then speed up and turn over. If I let it sit for a few more minutes, it started okay, and cold starting no problem whatsoever. I guess as the starter is so close to the pass. side exhaust, that it gets too hot and doesn't crank well.

After a while, the started died, I replaced it, and I never had problems again. Worth a check--mine, when it went, left me stranded....

 

It's most likely the starter. Mine did the same thing and was cured after I replaced it. The Starter gets hot from the manifold being next to it and the windings expand and rub on the enclosure of the starter, thus causing it to turn over harder. Other people on this site have experienced this also.

But first, check to make sure your alternator belt is good and snug and all your battery connections are tight, espesically on the ground side. You can have your charging system tested for nothing at O'reilly's for nothing. They have a little box they connect to the battery posts and they have you rev the motor a few times and it can tell you if there are any problems with the charging system.

 

I would check the ground first. A lot of hard start problems can be fixed with $20 worth of ground cables.

 

sorry to get in post but i got this question, does having long battery cables have to do with resistance and being too long gives it a slow start? cuz if so i got the same problem at my truck currently same thing happens lol and engine turns over but extremely slow....am begining to believe is battery starter motor or starter selenoid but i doubt cuz its got new starter motor, selenoid , except no new battery, thanks guys....
Delta-

 

the longer the cable is, the more resistance it has. the more resistance it has, the more current gets used in the cable leaving less for the starter. that is why you see people using 00 or 000 battery cables for remote batteries in the bed/trunk.

 

well good news, i fixed the problem , so far, turns out to be a bad battery , so bought a new one and now everything is fine....
thanks for reply bremen and all u

thanks
Deltasoft-

 

my 86 300 has always had a hard start after warmup....After rebuild I notice that the ground wire goes back to the transmission near the starter. I think I can cut about two feet of corroded wire off and attach it under the alternator on the block. Are there any problems with that? I would think the block has less resistance than the 0 wire.

 

I had the same problem with my 86 302 EFI. I changed the solinoid and have not a problem since. The solinoid cost about $14.

 

sounds good to me.. I don't know why the 300s did that.. my 351W is grounded on the block behind the alternator..

 

What a difference.....even on a cold start.
The exhaust heat cracks the insulation allowing water to corrode the wire. I'll
keep it mounted by the alternator.

 

I had the same problem in My '86. Did just what everyone else is saying. Replaced the battery, worked for a little while. Then replaced the pos and neg cables (connected to the block and frame), worked a little better. Replaced the solenoid, better still. Finally replaced starter and I haven't had the problem since. I am thinking of making a small heat shield to put between the stater and the manifold, or even one of the "oil filter radiators" (fins that slip over the filter) on it to see if that helps if the problem comes up again.

 

MR Hoov, can you explain the filter rad. I've never heard of it and am interested since I need a shield for my starter.