[bluebandit]

Hi Guys,

Well, had my GMC safari for less than a week and it's let me down already !! :banghead: Ah well, so much for a bargain !

It drove beautifully the first few days, no problem at all, then we had a big rain storm here on Thursday night and Friday it would crank like a good 'un but no start. Left it overnight to dry, charged up the battery but still no joy. Checked fuel tank has fuel in it, then popped off the dog house and had a poke about in there, got a hairdryer in there for 5 minutes to gently warm it all up, still no joy. I took the coil lead off the top of the distributor, put a nail in it so I could use it as a probe, held it to the block with some insulated pliers and I get a spark during cranking, it's dull orange in colour though and not very powerful ?? Also I was getting an arc from the back of the lead onto the pliers If I pulled it more than about 1/2 an inch away from the block ?

The distributor cap looked pretty worse for wear, black as **** inside, one of the spark plug terminals and leads was badly corroded and the rotor has seen better days so I don't think that's gonna be helping. I also couldn't pull the rotor off ? Is there some kind of locking nut or are they just on the distributor shaft real tight ?

Anyways, I've ordered a new coil, diz cap, rotor, plugs and leads which should arrive this week (can't just pop down the auto store for GMC parts here in England :violin: :lol: ). Does this sound like the likely culprits ?? They definitely need replacing anyway so no harm if this doesn't cure it.

I think I'm also gonna get some of that spray starting fluid (Ether) to see if it'll fire up on that once I've swapped the other bits to check it isn't fuel related, how do you get it into the intake ?? Is it just a case of unclipping the air filter hose and squirting some down there ?

Also, what's the easiest way to swap the spark plugs, looks pretty crowded in there ??

So, sorry for a long-ish post, but as this is my first American van wanted to sound you out on here for advice, any of which will be very gratefully received.

Cheers,

Andy

 

[Leeann_93]

Cap, rotor, plugs, wires and coil is where I'd start. Go through the wheel wells to get to the spark plugs. You'll need a wobbly to get to one plug. The rotor just pulls off. If it hasn't been done in a while, it'll take some serious pulling to get it off - once you do, I'd suggest polishing the shaft a bit (cover the rest of the distributor with a rag so the dust doesn't get into it). I had to do that on my Bravada just to get the rotor all the way installed so it wouldn't bump the cap (the PO didn't have it all the way down).

However, I'd suggest you do NOT spray starting fluid into the intake unless you feel like hurting yourself. Use carb cleaner at most...and don't use that unless you can't get 'er started without it. Yes, unclip the intake, open the butterfly and spray a shot in there.

 

[bluebandit]

Thanks for the advice, I guess it's a case of wheel off, jack it up then take off the wheel arch covers and dive in that way. I have a plug spanner for UK spec plugs, bet these ones are 5/8" drive though, so I'll pop to the toolshop tonight and get a wobbly plug wrench to suit.

Do these engines have trouble with starting fluid then ? I've used it before on engines with carburettors (VW stuff) where you can just pop off the air filter and squirt a bit into the butterfly's, pop the air filter back on and "boom", away she goes. Will it damage the intakes or injectors on these vortec engines ? Or is it that you need to pump a load in and end up getting your face burned off with a backflash up the air intake tube ?

I'll swap all the ignition bits out first and try that, but thought if that's a no go, then the starter fluid would tell me if it's a case of no fuel flow ?

Appreciate you taking the time to give me some advice.

Cheers,

Andy

 

[howie]

hi i live in the uk and have just brought 1997 gmc safari 4.3l if you needs spares for these you can get them next day from
USAutomotive
st martins way
bedford
mk42 0lf
01234 273155

you can find them on ebay too just ring them quote yuour chassis number they keep it on file for you then anything you want 98% of it is in stock if it has to come from the usa will take about 2 weeks to get to you and prices are cheap ive used tehm a few times already with no problem :banana:

 

[Leeann_93]

Thanks for the advice, I guess it's a case of wheel off, jack it up then take off the wheel arch covers and dive in that way. I have a plug spanner for UK spec plugs, bet these ones are 5/8" drive though, so I'll pop to the toolshop tonight and get a wobbly plug wrench to suit.

Do these engines have trouble with starting fluid then ? I've used it before on engines with carburettors (VW stuff) where you can just pop off the air filter and squirt a bit into the butterfly's, pop the air filter back on and "boom", away she goes. Will it damage the intakes or injectors on these vortec engines ? Or is it that you need to pump a load in and end up getting your face burned off with a backflash up the air intake tube ?

I'll swap all the ignition bits out first and try that, but thought if that's a no go, then the starter fluid would tell me if it's a case of no fuel flow ?

Appreciate you taking the time to give me some advice.

Cheers,

Andy

Starting fluid is fine for carbed vehicles. Don't use it on fuel injection vehicles. Brake cleaner does fine without the danger (the backflash part).

If you have a fuel injection pressure tester, that'll tell you without attempting to singe your eyebrows There's a schrader valve at the driver's side rear of the plenum where the fuel pressure and return lines enter/exit the plenum.

If you don't know how long it's been since it was done, get a new fuel filter for the rig, too. It's located just behind the driver's seat on the frame rail. You'll need flare nut (line) wrenches for that.

 

[Matrixx]

Hi bluebandit

That is definitely one of the culprits if not the culprit for you're no starting issues. A jumping spark with a weak coil will cause a lot of problems either way. Please keep us updated, Thanks.

 

[bluebandit]

Thanks for the replies, I ordered the bits from USAutomotive on Tuesday and they arrived at the local post office today, I'll pick them up tomorrow, fast service there.

I'll take your advice and lay off squirting highly volatile liquids into the engine until I've changed the other stuff out :lol:

I didn't realise it would be that simple to test fuel pressures, I assumed you'd have to break into a line and put some kind of meter in-line to get readings, had a quick look on line and there's kits with gauges to suit Schrader valves pretty cheap, so I'll pick one up if the ignition side of things doesn't cure it. How do you drop the pressure in the fuel system prior to attaching the meter ? Is there some kind of accessible pressure release bleed screw or something ?

I've not worked on injected cars before, just used them as daily drivers, so whilst I've tinkered with plenty of older carburreted stuff, this is all new to me from the tinkering point of view :think:

Speaking of fuel, just to clarify, when I turn the ignition key to on, I hear a mechanical click from the plenum area and a very quiet hum for a couple of seconds. Is this the system priming fuel into the plenum ?? it kinda sounds like a solenoid moving a valve or something, and it clicks off again when I turn the ignition off. A little confused as I thought the pump was in the fuel tank itself, so was trying to listen down there for anything going on ??

Cheers,

Andy

P.s. have ordered a Haynes manual as well :thumbup:

 

[Leeann_93]

You don't have to drop the pressure - the purpose of the Schrader valve (like a tire stem) is to hold the pressure despite you screwing a gauge to it.

The pump is in fact in the tank. When you turn on the key, it primes the system for 3 seconds. You might be hearing the 'spider' - the fuel injector body + fuel pressure regulator - being primed. I don't think I hear anything there on mine, though - my hum definitely comes from the tank.

 

[bluebandit]

Okey Dokey, now we're getting somewhere...

Swapped out all the ignition bits on the weekend, dizzy, rotor, plugs, leads and coil (Whoever designed those spark plugs in that position needs to be punished !! :doh: )

Still no joy, so called in a friend of a friend who's a mobile tuner to give me a hand, we checked and no fuel pressure at all and no fuel pump activation, so, checked the fuse panel and ECM B, all fine, had a dig around in the engine bay for the fuel pump relay and eventually find it and another identical relay hanging down the side of the block, upside down !!! Anyway, could hear one of these clicking but nothing from the other, swapped the 2 over and hey presto...up she fired !!!!

I'm presuming that because my drive is on a slope, when we had the heavy rains moisture found it's way onto the relay terminals and gunked one up.

So hopefully a new relay (and mounting them the right way up ! )should solve the problem.

Just a quick question though, the relay we pulled out to test the faulty one, what does it do !!! There's a picture of the 2 in the haynes manual side by side, one is the fuel pump relay ( the faulty one ) is the other one the A/C relay or something ??? Tried deciphering the schematics but can't see any other relays like this on the fuel or ignition circuits :think: ??

Thanks for your help, hopefully with a new relay we should be back up and running.

 

[astro355]

Good job! I love to hear stories like this were owners took the time to diagnose the problem(s) before changing a punch of parts for a lot of money and then getting upset about it. Hanging the relays upside won't damage them but hanging them over the engine block so they can absorb that heat will do it. The electrical connectors for those relays are called weatherpack connectors. They have a rubber seal on them that prevents moisture from getting inside.

 

[bluebandit]

Just ordered a couple of the relays today, so should be here tomorrow.

Incidentally, what does that other relay do ?? I found a thread on here that says it's a "shift relay" ? Is it something to do with the neutral safety switch on the column shift ?

Cheers,

Andy

 

[bluebandit]

Yep, Just to finish this post off, the relay did the trick. Ordered a couple of them from USAutomotive, swapped out the bad one and she starts first crank in all weathers, result !

.....but, and this may be a world record......

Got everything back together, reversed off the drive, drove forward and got about 6 feet and a brake line split !!

Total distance travelled between breakdowns ..... 22 feet ... is this a world record ! :lol:

The line is replaced now and we're back up and running, I'll post a bit more about this in the brakes forum as the cause may be of interest.

Cheers,

Andy

 

[Matrixx]

Thanks for the update bluebandit and I'm glad you got things sorted out.

Either way, I'm glad you changed out the ignition parts, from what you described, it would have been another problem down the road more sooner than later that's for sure.