Here i sit, quite a bit less than guntled about shelling out $300 for a repair that didn't actually fix what I took it in for. Not only that, but they wanted to keep my truck overnight to try it out in the morning to see if they can find more stuff to fix. The same facility has a rent-a-wreck type place in it also (hence, how I got to work today, while they ****ed the day away trying to diagnose the problem) .

This is a '84 F150 which hesitates when starting, kind of like the battery is almost dead (but the battery is new and the cables have been checked). I told them that the timing had been checked by 2 different mechanics, but they insisted that it is a timing problem. I suspect that it may either be the starter or the solenoid, but I don't think they even checked those (after having the damn truck all day). I fear that it may be another faulty engine ECU module because one thing hey said tonight made sense... That the hesitation is actually the module retarding the spark while I'm trying to start the engine. The engine was rebuilt in March of this year and the engine builders had to replace the ECU at that time because they couldn't get the timing right after the rebuild. The $300 today was for a new harmonic dampener/pulley (which supposedly affected the timing), labor for the job, and about $65 for an all day diagnosis session. The old dampener off my truck was shown to me... The rubber on that one was about to fail, so I didn't dispute the repair (since I can't really prove whether that one actually came off my truck or not).

The hesitation persisted as soon as I left the shop tonight. I don't want to take it back to them because I'm sure they're full of it (they approached me tonight like I'm supposed to just let them keep this 20 year old truck for as long as they can find stuff wrong with it), but I'm not quite sure what to try next. Finding a reputable repair shop in this town is becoming quite a chore. I've already been ripped off to the tune of $650 for a new carb from a different shop in town. It shouldn't have cost that much, but they'd gotten halfway into the rebuild and discovered that the whole carb body needed to be replaced. Should I just replace the starter, or what? Maybe just break down and take it to the dealer? I don't know...

 

been there done that I think that is why they make guns forwell the hermonic balancer pully is known to do some of that.I ran into the same problem with my carb my friend the mech.was puting on my air cleaner and was fighting with it real hard I told him leave it alone but my carb started to leak hum he said not me morons went the bone yard found an old granda took it carb then rebuild it no back to the problem as I tell everyone I know to let the veicle run get some carbcleaner and spray on the outside of the carb around the base and stuff if the r.p.m changes you need to change gaskets or carb gaskets .also check every vacume line oh and while you are at change that old p.c.v that will cause enogh problems in it self.now if you feel froggy try this nowfind a vacume gageee and disconect the vacume advance if have one and re set timing if it has the electric plug type with the computer try some electric cleaner if the plug inside is green,well let me know I love my old truck 1980 ps.I would rather buy a book read the hell out of it and do my best than get stood up by these so called mech. hey we all make mistakes by the way it only cost me 20 dollars for the carb 15 for the rebuild kit and 5 for the cleaner and brushes the carb is so simple to rebuild sorry about my spelling I'm old and crazy not a teacher keep sane and let me know

blumpy

 

Does the hesitation when you try to start the engine happen while you still have the key turned to the "start" position, or after you release the key back to the "run" position after the engine has fired up? What I'm trying to determine is if the hesitation is in the starting circuit or in the engine run circuit?

If the hesitation is during the "start" cycle, the starter will vary in sound as it's cranking the engine before it starts. That is, it'll go fast then slow down, as though it's "grunting" through a tough rotation. It won't make a smooth, even whirring sound as you hold the key in the "start" position.

If the hesitation in the starting circuit, it has to be one of three things (since you say the battery is new). I'd look at the following three items in this order:

(1) Disconnect both battery cables and revisit the inspection of the cables. Specifically check them right where the cables go into the lead terminals that connect to the battery. Flex them at this point, so you can look down under the insulation to see if there's any corrosion in there. If there is, you may have a high resistance connection that's not passing the amperage necessary to crank the starter at full strength. Cable replacement is easy and straight forward, and should be under $20 if you buy them at your local auto parts store and replace them yourself (it's a simple job). You can expect to probably find some corrosion at the joint, but if it looks real nasty down in there I'd strongly consider replacement as a good possibility. Also, check the connection at the other end of each cable, particularly the negative one where it attaches to the frame. If there's any doubt, remove the connection and sandpaper both of the mating surfaces before bolting it back together. The positive battery cable will run directly to a terminal on your starter, where it attaches to a copper stud. There's seldom corrosion at the starter, but check it out anyway - you might have a loose connection there. (CAUTION: When you're working on the positive starter cable connection with a wrench, be sure you're battery is disconnected, otherwise it'll be 4th of July if you touch the frame with your wrench!) Also, are your battery terminals shiny clean, as well as the mating surfaces on the connectors? If not, sand them a bit with 200-grit paper or clean them with a battery terminal cleaning tool (less that $3.00 at your local auto store).

(2) As for the solenoid - has it ever been replaced? After 1000's of starts, they do get burned contacts internally and develop a high resistance, which results in a hesitation when the starter is rolling over. Solenoids are relatively inexpensive (about $15.00), easy to replace (just be sure to disconnect the battery before you start installing it), and available at your local auto store. Buy the best one you can that'lll fit your truck, if the store offers two or more at different prices. The better ones have larger surface areas on the internal contacts, which results in fewer amps per square inch under load (when starting) and will last much longer. The cheap ones tend to burn out or stick in a relatively short time. Personally, I just replace the solenoid if I have any reason to believe it's even THINKING about giving me a problem.

(3) And last, you could be having trouble caused by bad (worn down) brushes in the starter itself. After all the starts your truck has gone through over the years, it might just be time to replace it. Don't try to replace the brushes, just get a rebuilt unit from your local auto parts store, because by the time the brushes are worn down the commutator inside (what the brushes ride against to make contact with the rotor) is probably egg-shaped and needs turning on a lathe. A re-manufactured starter will probably cost less that $100, and you return your old one (as a "core" to be rebuilt). It's a little tough to replace, because of the location, but isn't rocket science if you have a minimal set of sockets and open-end wrenches. Tends to be a greasy, dirty job, done from underneath in an awkward position - and the starter is heavy to hold (probably about 20 lbs). You don't say how many miles you have on your truck, but a starter should last for 100,000 and 150,000 miles. It depends on how much it's been used. I just replaced mine on my '87 at 117,000.

Now, if the hesitation is in the engine once you release the key from the "start" position, well, that's a who-o-o-le 'nother story! I won't even try to analyze that kind of problem here, without knowing much more about it. If this is the situation, then problems with your carb, or ECU, or timing, or a whole bunch of other things COULD (but not necessarily be) causing the hesitation. However, if the hesitation is in the starting circuit, don't let anyone BS you that timing, the ECU, the carb, or anything else is the source of the problem because the engine isn't running at this point.

And regarding the shop replacing your harmonic dampener/ pulley, yes, it is not unheard of to have the rubber slip between the hub and the outer pulley. Because the I6, 30CI, 4.9L engine is a "flat-head", the valve timing is run via pushrods operating directly off a camshaft in lower end (that is, there's no "timing belt" like on overhead cam vehicles) and the distributor rotor is driven by a worm gear that's also on the valve camshaft. In short, the timing CAN'T change because the rubber in the harmonic dampener slips. The only problem created when the rubber slips is that the timing marks (the "Vee"-shaped notches) on the front side of the outer pulley rim move relative to the engine crankshaft (since the hub is keyed to the crank). If someone subsequently tries to time the engine using these marks, they'll set the timing way off (depending on how much slippage has occurred) and wonder why the engine doesn't run right. This problem can drive you nuts, until you figure it out. A slip in the rubber should not cause an operating problem ... until the next time you try to time the engine. Of course, if the rubber is really loose and slips a lot, or tears itself to pieces, then you'll lose your alternator, power steering pump, the water pump, the engine fan, and whatever else is driven by the belt all at once. There are a number of posts on this forum regarding this problem.

I hope this helps.

Please post back as to what you find. Good luck!!

 

Thanks for the response! It's definately hesitating during the crank, not after the start. It's got 216,000 miles on it; I've only owned it for about a year, but suffice it to say that a new starter and solenoid would not be a bad idea.

The shop from yesterday said the timing was 15 degrees off because of the Harmonic dampener slip, and they fixed that (but gave me some sob story about how much more can go wrong with the engine timing being 15deg off... ) . I have a mechanic in Ohio that I trust, so I'll leave the rest of the work to him this weekend. The truck started fine this morning, but it's an intermittent problem... I'll see how it does at lunch time and this evening. Thanks again!

 

Turns out it was the starter. I also had the solenoid replaced for good measure. Sounds completely different and starts faster than before .

 

Thanks for posting back at to what the real problem was!

In your original post, you said:

"I fear that it may be another faulty engine ECU module because one thing they said tonight made sense... That the hesitation is actually the module retarding the spark while I'm trying to start the engine. The engine was rebuilt in March of this year and the engine builders had to replace the ECU at that time because they couldn't get the timing right after the rebuild."

Yeah, right! NOT! Now that you know that the rubber can slip in the harmonic dampener and throw the reference point for setting the timing off, I hope the "engine rebuilders" paid to replace that ECU and not you. Now there's the kind of problem mis-diagnosis that I find upsetting. It had (and has) absolutely nothing to do with your starting problem. Even IF they did replace the ECU, they had to find that it hadn't fixed their inability to correctly time the engine when they tried to set it the next time. They must have just set the timing "by ear", said "to heck with it", and hoped for the best.

 

Yeah... It seems that when a mechanic sees me bringing in a 20 year old truck and sees that I still want to spend money on it, they go to the "johnson rod" strategy and try to milk me dry . Oh well, it all turned out for the best. Thanks for help.