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Buick HALP! plz


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So the Buick Park Avenue I acquired a couple of weeks ago has FTPd, and all of my attempts to get it working again have hitherto proven fruitless.  I've posted about this in the Stupid Question Ask a Shiter thread and had a few suggestions / pointers which I've tried, but I'm not sure how many people actually read that thread so I thought I'd start a new one, which can then go on to be an update thread about the car for as long as I keep it.

 

The car was running fine up to Friday before last, and hadn't given any indications of impending doom.  I went to it on the Saturday and it started straight up, ran for two seconds then died, and it's not started since.  The engine is the 3.8-litre V6 which has been powering GM products since the late 14th century, albeit improved* with the addition of fuel injection and coil pack ignition.

 

Thus far I have been able to ascertain the following:

 

-It has sparks - as demonstrated both by pulling an HT lead and sticking it on a spare spark plug sat on the engine, and by the fact that it fires up and runs on Easystart.

 

-It has compression - I've not done a compression test or owt but you can hear it has plenty of it by the sound it makes when turning over on the starter.

 

-It has fuel - I pulled the inlet hose off the fuel rail and turned the ignition on and it shot a geyser of petrol all over the engine bay as the pump primed.  The pump is also pumping as it should when the engine is cranked over.

 

-It has power to the injectors - not a full 12v, but then I assume the injectors may run on a lower voltage anyway.

 

-I was able to ascertain, with the help* of the world's shittest test light, that the injectors are pulsing, which suggests that the ECU is working as it should.

 

So it has sparks, fuel and compression, so it should start, right?  So WTF is going on?

 

Dodgerover suggested it could be plugs - they do look pretty ancient to be fair (and one of the leads on the front bank left its metal clip thing on the plug when I pulled the lead off), so I'm going to replace them anyway as I can get a new set for a tenner, but surely if they're so shagged that the engine won't even cough, it wouldn't fire straight up and run "normally" on Easystart?

 

One of the American forums I looked at suggested that it could be one naff injector, which can then knock out all the rest, but I've tried unplugging each injector in turn to no avail.

 

I'm rapidly running out of ideas.  I'm not going to take it to a garage - even if I could find one locally which knew these engines (I assume it's the same engine as was used in the Blazer, but they only sold about three of those over here), with the other issues the car has it's really not worth spending that sort of money on.  I'm therefore hoping that somebody will come up with something obvious that I've overlooked (which is quite likely - I'm not much of a mechanic) and she'll soon be back to wallowing around the back lanes of Norfolk in her two working gears like some escapee from a low-budget Florida trailer park.

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There is a factory immobiliser (chip in the key, quite modern for 1991), but don't think it's that as a. the immobiliser light goes out on the dash as it should and b. the fuel pump wouldn't be kicking in if it had immobilised itself.

 

I should also add that I've interrogated the on-board diagnostics (OBD1, so bridge two pins on the plug with a paper clip and count the EML flashes), and it showed no fault codes.

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When you pull the plugs, are they wet?  If they're dry that suggests fuel is getting to the injectors but not through them, Id'v'e thought.  Easy Start is probably able to flush through since it's thinner than regular fuel.

Good point.

 

Will it fire on WD40?

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Is it sparking at the appropriate moment? Some old Fords had a DIS module which, if memory serves, controlled when the spark appeared. DIS fault = spark at worng point = no start. Wonder if this uses a similar setup similar.

 

Is the wiring to the crank sensor in good condition?

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Easy start will get through as you spray it straight into the intake so it doesn't go via the fuel system at all.

 

I'd pull an injector and see if it's actually firing. If your plugs are dry and it's not running it suggests to me that the fuel isn't getting as far as the cylinders.

 

Whereabouts are you and the car?

 

Worth trying...

 

Disconnect the battery overnight (if you have any codes to hand!) just to reset any electronics. Also while the battery is off disconnect and reconnect any ECU connections you can readily access in case there's a simple connection problem.

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I am having a similar issue with my Aurora where the plugs are new, produce spark, the fuel pump works and delivers fuel to the injectors (which however are leaking now) yet don't get the engine to run unless I spray fuel directly into the throttle body. I narrowed it down to the injectors being stuck open/closed or GM's passkey anti theft system (with the "chip" in the key blade) which seems to be a very common failure now. The system basically cannot read the resistance of the chip anymore and therefore thinks the key isn't the right one. You can buy resistor kits to bypass the system if nothing else helps. I haven't tried mine yet, but its cheap and easy enough to give it a try.

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Tesco's finest! I was running it on that before though with no problems. It's designed to run on American 91-octane monkey piss, so it should be OK.

I know someone who had a problem with contaminated Tesco piss recently, so don't rule it out. Maybe try bunging some meths in the tank to get rid of any excess water, as that could cause it to stall. Rules it out if nothing else.

 

Edit: actually I'm not sure if that old trick only works on carb fed, so feel free to ignore.

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I know someone who had a problem with contaminated Tesco piss recently, so don't rule it out. Maybe try bunging some meths in the tank to get rid of any excess water, as that could cause it to stall. Rules it out if nothing else.

Been there, done that, bought the T shirt.

 

Rebuilt the entire damned ignition system and had the carb apart twice in the Skoda before discovering it was dodgy fuel. It ran fine for a couple of days after I fuelled up too, which I never quite figured out. I can only guess that there was some reaction with one of the additives or something in the existing fuel in the tank that took time.

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Crank position sensor is problematic and can cause those engines to not start or just cut out not 100% savvy with the location of it but no doubt itll be near the crank somewhere :mrgreen:

 

That's exactly what it was when mine displayed exactly those symptoms.

Sadly the CPS is not where you would like it to be.

 

0996b43f8021af6d.gif

 

It's a pulley off job.

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Yup +1 for the crank shaft position sensor. I had it happen on my pug cab. If the engine doesn't know where the crank is, it won't fire. It will still spin on the starter and fire on easystart though.

.... If there is no spark, how does EzStart fire up the engine?

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Thanks for all the replies thus far. 

 

Crank sensor was one of my first thoughts, but surely if the sensor was dodgy and was telling the coils to fire at the wrong time, the engine would have farted and backfired on Easystart rather than starting up and running normally for as long as the magic potion was sprayed into the intake?  Also would a dodgy sensor not have thrown up a fault code?

 

Good point re plugs - they were bone dry when I took them out, although to be fair it had been a while since I'd tried cranking the car over.  There's definitely fuel getting to the fuel rail though, and it appears to be getting round the rail as the Schrader valve at the top of the return hose lets out a spray of petrol when pressed in.  I still find it odd that the injectors wouldn't be firing - there's fuel getting round the rail and the injectors appear to be getting the signal to fire from the ECU, so unless all six injectors have crapped themselves at once I don't understand why they would not be, y'know, injecting fuel?

 

Edit: I don't think it's dodgy fuel as I filled the Toyota up from the same pump at the same time, and that's been fine.

 

Edit 2: would the ECU not get its info on when to tell the injectors to fire from the crank sensor?  I was getting a nice regular flash from the test light when cranking the engine over.

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Does this engine have three double-ended coils? If so the ignition may be triggered by a crankshaft sensor (which is working if you have sparks enough to run on esy start)

The injection pulses to the injectors will need to be timed from a camshaft sensor.

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Yep, three double-ended coils by the look of it.  I think it's a wasted spark system.  Sounds like both crank and cam sensors are working then.

 

It's sounding more like an injector issue I think.  Do injectors normally run off a full 12v?  I was getting a reading of between 6 and 8.5 when I put the multimeter across.

 

The other possibility is fuel pressure I suppose - there's definitely fuel getting through, but I'm not sure whether it's at a high enough pressure to enable the injectors to work - not sure how I'd go about measuring that unless I can find a fuel pressure gauge which connects to the oversized Schrader valve on the fuel rail.  I'm not sure what sort of pressure a petrol EFI system normally runs at - I know it's higher than a carb and a lot lower than a common rail diesel, but that's about as far as my knowledge goes...

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Can you borrow or buy a set of noid lights?

 

They plug in where the injector goes and flash when the ECU is trying to fire them.

 

They are about £12 on ebay, it will help you rule in/out whether its electrickery or actual injector problem.

 

Measuring voltages probably won't quite work, although I would have thought you should get 0v/no continuity apart from when it's actually squirting. But electrics arent really my bag.

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I think Esasy start is misleading..........put enough in and you dont need a spark to ignite it.......compression is enough.

 

If the plugs are dry after spinning over then it has to be fuel........and if you have fuel pressure (enough?) in the rail then you need to find out if the injectors are getting a signal as per Dave Q's post...……...as long as there isn't some aftermarket immobiliser that's kicked in

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Is it difficult to pull the injectors out? There’s a seal or o-ring that you might need to replace afterwards (or you might not) but it’s the only way to be sure.

It looks a bit awkward tbh - looks like the fuel rail would have to be completely removed.

 

 

Can you borrow or buy a set of noid lights?

 

They plug in where the injector goes and flash when the ECU is trying to fire them.

 

They are about £12 on ebay, it will help you rule in/out whether its electrickery or actual injector problem.

 

Measuring voltages probably won't quite work, although I would have thought you should get 0v/no continuity apart from when it's actually squirting. But electrics arent really my bag.

I used a test light to do the same thing - ran it from the battery positive to the earth wire on the injector plug, and it flashed regularly as I turned the engine over on the starter.

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May not be of any use for you at all. There's a sorry looking (crashed) Buick around the back of my local Yankee parts place. I used to see it wafting about. I fear it may go the the scrapers.

May be worth a call.

https://castleford.cylex-uk.co.uk/company/castleford-american-autos--cas-am--15776661.html

Think the main website has gone down.

 

I think it's a 3.8.

post-5414-0-27264900-1549915811_thumb.jpg

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