Help! 91 Firebird cranks but will not start

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Help! 91 Firebird cranks but will not start

Post by alexgibson » Tue Feb 03, 2015 10:28 pm

Hi all, I have been struggling badly with my recently bought Firebird. It worked OK to drive home but had tendency to stall at lights etc, ran horrifically rich, lumpy as anything and since getting it back this has got immediately worse and I have only driven it once, had a failure to start and had to be jumped to get home. Now the car will not even start to get to the garage that last worked on it, who I am promised will make good the exhaust and brakes, which are shot.

Not good.

I suspected VATS issues preventing starting. I have non-destructively modified the VATS by disconnecting the cylinder wiring at the column connector, and plugging in a resistor pack to match the key.

This has provoked a change - the car now turns over every time, and the security light goes not light. However the car does not start - every few seconds of cranking there is a bit of explosion but nothing continues.

Continuing down the VATS line, I have tried the 10 minute passkey/passkey 2 relearn process, but the security light was never on, and after trying to start, then leaving key in 'on' position for 10 mins and trying again, there was no change.

I have now made up a VATS bypass module, to give a 50hz square wave into the BCM to mimick a happy VATS module, in case this is broken and not enabling the injectors.

I suspect, however, a problem with either fuel getting to the engine, or spark. I tried to order a distributor cap and rotor from USAutomotive on eBay which arrived today, but seems fairly low quality and the rotor does not touch the cap pins - I may be missing something or have the wrong part. I will try to order AC Delco.

I put more petrol in the tank and fuel gauge is high and went higher. When turning the car on there is a little whir from the back, but unsure how to tell whether the fuel pump us working properly. The fuel filters may not have been changed.

I need to get my car running ASAP for several reasons - doesn't have to be perfect but must start and move about! Can anyone help suggest troubleshooting tips I can try? I may do them myself or get a mobile mechanic involved - who us likely to have no Pontiac experience...

Thanks for any bright ideas to get started!!!!

My next action will be to read diagnostic codes using paper clip method...

Cheers
Alex
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Re: Help! 91 Firebird cranks but will not start

Post by bhm1712 » Tue Feb 03, 2015 10:57 pm

I have moved this into technical area.

If the starter is cranking then it's not Vats which is at fault.

If vats module didn't register the correct resistance in the key chip then the starter would not crank and you wouldn't have any fuel gong in at all to create the "explosions" you speak of.

Sounds more likely you have a fueling issue or similar.

Somebody in the know more than me will be along soon to help in more detail
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Re: Help! 91 Firebird cranks but will not start

Post by alexgibson » Tue Feb 03, 2015 11:02 pm

Thanks, I posted from a phone and was just trying to tidy this into the correct part of the forum myself, so there is now a duplicate in Engine etc section - I will remove that one.
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Re: Help! 91 Firebird cranks but will not start

Post by alexgibson » Tue Feb 03, 2015 11:24 pm

Thanks Ian,
as I understand it there can be a couple of different kinds of VATS problem. Most common one I should have solved by bypassing the resistor key. Less common is for the VATS module itself to go bad, and I think this can cause the injectors not to work.

A fuelling issue does feel likely - it is like an out of petrol situation. Quite regular though.

I recorded some sound if cranking - will try to upload
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Re: Help! 91 Firebird cranks but will not start

Post by alexgibson » Wed Feb 04, 2015 11:48 pm

There are no diagnostic error codes - just flashes 1-2, 1-2....

So how can I best diagnose which bit of the fuelling system is to blame? How many parts could it be? I may be buying the whole set and getting a mobile mechanic to do the lot until it starts...
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Re: Help! 91 Firebird cranks but will not start

Post by NOODLES » Fri Feb 06, 2015 7:49 pm

Spray in some carb cleaner or quick start thru the airbox in short bursts while someone cranks it and see if it fires. If it does its fuel prob. If it doesnt then check for spark issues
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Re: Help! 91 Firebird cranks but will not start

Post by alexgibson » Sun Feb 08, 2015 8:42 pm

Great, thanks I will do exactly that ASAP and report back! :)

*googles carb cleaner*
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Re: Help! 91 Firebird cranks but will not start

Post by alexgibson » Sun Feb 15, 2015 9:09 pm

Hi, I got some Wynn's carburetor and fuel injection cleaner from Halfords, and with my neighbour turning the key, sprayed it into the air intake (the end of the flexible linkage that comes off the metal air intake of the engine).

This seemed to do nothing.

I also replaced the distributor cap and rotor with a cheap replacement bought from USAutomotive on eBay. After a lot of faffing about trying to get the screws to locate, as it's in such an awkward location, I think I did this properly. I could see that the old distributor cap spring pin was worn away completely. It is likely this explains why the car was running so badly, at least in part.

However, the car still did not start.

The starter motor was still cranking, but if anything I have taken a step backwards, because there were none of the regular attempts to fire I heard previously.

The battery was pretty low by this point though - <10V - so I am hopeful that this could be the cause and I've actually fixed the issue.

If not, my hit list to fix the issue is:

1) Bypass VATS using a signal generator straight into the Body Control Module (BCM) - I have 2 circuits now, one I made and one I bought. However the car cranks every time with the resistor chip bypass and the security light goes out a second after turning the ignition to 'on', so I'm unsure whether VATS is at fault - but if it is, it could be killing the injectors,
2) Check the spark plugs just by taking out and looking
3) Buy a new petrol pump and fuel filter, and get a mobile mechanic out to change these - unless anyone here can confirm it's easy to do the fuel filter without a ramp?
4) ?????? Tow it to Autopontiac? Prefer not to...

I would be grateful if anyone has any ideas?
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Re: Help! 91 Firebird cranks but will not start

Post by NOODLES » Mon Feb 16, 2015 7:34 pm

Check for spark buy pulling a plug out and while still connected to the ht lead, Earth the prong to the engine block and look for a spark while someone cranks it...... wear gloves! Also use a multi meter and check for any bad earths or loose leads.
My best advise to you is simple...... phone Robin! Were all just guessing, Robin will probably tell you within minutes what the problem is over the phone. No point throwing money at it on guess work. Hes always happy to help, and if you can pop over to him he will even make you a cuppa :)
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Re: Help! 91 Firebird cranks but will not start

Post by alexgibson » Wed Feb 18, 2015 2:32 pm

OK so there have been a few developments!

I followed the advice above and skipped VATS and went to #2 on my list - thanks Noodles!

With the help of my neighbour, I tested the ignition 2nd stage by putting a new spark plug on the end of one of the leads, earth against the engine casing, and there was a spark, no problem.

I then took out one of the spark plugs and it was a) black and b) wet.

So, we cleaned and put back one of the spark plugs and the car tried to fire.

We took out and cleaned all the spark plugs, only to find that the #1 cylinder spark plug lead was completely disconnected! No wonder it ran badly.

Now firing on all cylinders, the car started relatively easily, needing just a foot on the accelerator to encourage it.

The car ran massively more smoothly, but was not able to idle - it just stalled. I managed to reverse a bit and tidy up my parking within the communal garage area it is stood in.

Then on my neighbour's advice I ran the car for about a minute at 3000rpm to see if things cleaned themselves up a bit.

Then, disaster! I could see some smoke - more than expected from the blow in the front of the exhaust - but there was actually fire under the bonnet!

This was a small brown wire going to the back of the starter motor (solenoid?) which was near to or actually touching the exhaust, which was obviously hot and has leaking exhaust gas.

Having doused the area with screen wash, we checked that the wire was not near the exhaust, and started the car briefly - it still fires up. Stopped it immediately and checked for a good while that there was no residual heat or smoke.

I now have a tricky situation, because all the effort to start the car was to get it back to the garage that serviced and MOT'd it in September, for them to look at the exhaust, which blows, and may have partly caused this issue, and the brakes, which throb badly.

Now I find that having been to them for a service, a HT lead was completely out, and there was loose wiring causing a fire. In addition to one pop-up headlight not working, which I fixed myself.

I bought the car under contract that it would pass an MOT again, within a week, which from a trip to Kwik-Fit was clearly not going to happen without work. The previous owner had already spent the money, and could not take the car back. He had recourse against the garage and agreed with them for me to take it back to them to sort the exhaust and brakes.

I now need to contact them and understand exactly what they will do to help recover this situation, because the car was clearly in a severely bad way, but I'm concerned that it ever left them like this! And I'm a bit scared to drive it to Birmingham in case there are any other lurking wiring issues which could cause a fire!

At least the car now starts and moves, and I have fixed the VATS and a headlight! It's progress...! I will now buy 3 fire extinguishers, one for this and one for my wife's car and my BMW! I never want to have that moment again!!
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Re: Help! 91 Firebird cranks but will not start

Post by Davy J » Wed Feb 18, 2015 4:13 pm

That fire must have been a bit scarey Alex.Glad that some progress has been made. If it was me, I would forget about going to Birmingham ( into the unknown as to a quality job being done) and instead drive to Autopontiac, in Hounslow, it's nearer aswell. Give Robin a ring, sure he can get this sorted for you.
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Re: Help! 91 Firebird cranks but will not start

Post by alexgibson » Wed Feb 18, 2015 6:30 pm

It was rather a shock to see actual flames under the bonnet - it's a 'Firebird' but even so... at least I can be sure it had nothing to do with the successful work we did on the ignition.

You're right that it's an unknown quantity to take it back to Birmingham - I'd want to be there to see the work to know what has happened! I've written to them and sought their assistance in getting the car back to them safely and to properly get it up to safe standard. If they are willing to stand by their work, as they agreed to, then great.

I will certainly hold onto the option of taking the car to Autopontiac for a proper tune-up. I have 100% confidence in their work based on the excellent job Robin did on my previous, near-identical car - he had it running at top efficiency. I also had a less positive experience albeit indirectly (important to say this is based on my personal feeling due to the consequences, and mostly down to a less than competent insurance company contacting them in an inappropriate manner, leading to the wrong output), so I just don't want to be completely reliant on one specialist however well regarded.

It did feel extremely good, with my neighbour's experienced help, to have actually sorted out the ignition problem at the roadside without any garage - and to demystify a crucial part of the car in the process. Less good to find the car even more riddled with issues than I knew already including things any garage should be able to get right! That said, refitting #1 spark plug on the V6 past the alternator bracket is ridiculous! I am sure the design of this didn't help!

I know the car will need a lot of work to get it anywhere near the standard my previous one was in, and I bought it as a project, so I want to stay completely on top of the work, do anything I am (or can become) competent to do myself, get the basic car sorted out to a reasonable level, and then properly plan a restoration project.

Now, apart from repairing the damage from the fire and checking whether there is anything else where it shouldn't be in the engine bay...

Where next to to diagnose the car starting OK, running on all 6 cylinders, but cutting out rather than idling?

- Could it be the spark plugs still? Maybe not the right gap?
- Fuel filter? I have ordered an AC Delco one from the States
- (lack of?) oxygen sensor on the exhaust?
- ??? other?

Having actually run the car now, I will check to see if it is throwing any error codes. Before, it was just 1-2, 1-2... I'm not sure how long it has to run to register a code, but it sure should have seen something it didn't like today! I know I did!
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Re: Help! 91 Firebird cranks but will not start

Post by alexgibson » Wed Feb 18, 2015 11:06 pm

Still no error codes...! How much does the car gave to run before it sends an error code? Seems odd that it can get as far as stalling a few times without logging an error?
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Re: Help! 91 Firebird cranks but will not start

Post by NOODLES » Thu Feb 19, 2015 9:14 pm

Glad its running mate. Always worth purservering. Buy a new set of plugs. For 20 quid its a no brainer. Idle might just be because it hasnt had a good run, but my bet is most likely a leaky vacuum pipe or throttle position sensor. Check all the connections and wires are tightly fitted. As for the fire, the exhaust will get very hot running at 3k rpm for a couple of mins. Check the wire and replace a section if needed. Slip a piece of rubber pipe, like fuel pipeing, over the wire where its close to a heat source, and cable tie wires out the way. It probably melted the coating and earthed out.
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Re: Help! 91 Firebird cranks but will not start

Post by NOODLES » Thu Feb 19, 2015 9:16 pm

Oh, and vacuum leaks prob wont show up on codes so defo worth a check. And not every problem will code up so dont fixate to much on the fact you have no error codes. :)
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Re: Help! 91 Firebird cranks but will not start

Post by alexgibson » Thu Feb 19, 2015 11:50 pm

Good call. New AC Delco psk spark plugs ordered. Vacuum pipes may well be an issue - at least a couple were disconnected and I already put back together. I will check for more., as well as checking all the wiring.

I may get the engine bay cleaned as so much work is needed. Anyone got solid experience of good and bad ways to do this?
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Re: Help! 91 Firebird cranks but will not start

Post by alexgibson » Sat Feb 21, 2015 2:23 pm

I had a mobile mechanic over to have a quick look at the Firebird today. He broke 2 of the spark plugs taking them out which was not so good, rendering the car immobile again. :'( However he did seem a straight-up sort of chap, and seemed confident to work on the car and quote for work up front, being clear to me what he felt was generic and quick work vs a more specialist job it would take him time to figure out at my expense (or, as has been suggested, should be taken to Robin!) He got that I preferred to source correct parts and didn't mind waiting for the right ones, and was happy for me to work on the car and bring the jobs I didn't want to him...

He did a couple of useful (if a bit basic) tests:

1) compression test for the left bank and pronounced this OK - reading was 11 (psi?). He said this was good news from the point of view of most likely not having to strip the engine down
2) He checked the oil - this was a mess - overfilled, dark in colour, which I could see for myself, and smelling a bit of petrol, which he though could be due to oil overfill/wrong viscosity of oil.

He recommended:

1) drain and refresh the oil with correct viscosity.
2) replace spark plugs and leads, check and refit the distributor cap
3) replace oil filter
4) check injector spray pattern (a friend from Reading Hackspace suggested this also)

Important thing to him was to do all those things before attempting to turn the car over again.

He pointed out a number of previous bodges done on the car - such as exhaust paste on the joint between the headers and the downpipes. This matches the exhaust and a couple of sills underneath...

I mentioned the exhaust missing a catalytic converter and lack of O2 sensor - he said this would cause the engine to run extremely over-rich, at maximum fuel, and could explain the presence of fuel in the oil. I noted the ridiculous over-consumption of petrol down from Birmingham to Reading.

I haven't yet heard back from the Birmingham garage, and I am getting bad vibes about how the car got through an MOT at the same garage. The previous owner had mentioned them saying something about the timing still being off - no wonder given they left a H/T lead off.

It seems there's no point doing the servicing only to run the car open-loop and mess it all up again, which means doing the exhaust work as well, all at the same time...

So I will contact the Birmingham garage and find out what they are actually willing to do...
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Re: Help! 91 Firebird cranks but will not start

Post by alexgibson » Tue Jan 26, 2016 9:58 pm

After a long gap where I did nothing at all, I replaced all distributor leads, cap and rotor, all spark plugs and fuel and oil filter with new AC Delco. Car now starts well, but emissions still terrible. I have an ALDL-USB adapter - does anyone know good software to read my car's inner monologue about it all?
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