tony_ack 0 Posted October 12, 2011 GRRRRRR! The car is a 1995 VR6, with original OBD I engine, Scrick manifold and Stealth remap. The car has been starting fine while I've had it, and continued to start okay after the Schrick/remap, however in the last few weeks it has developed a cold starting problem, and I have not done any work to the car that may have caused it. Sometimes (about 1 time in 5) when I try to start the car it will turn over but will not fire up (it starts first time the other 4 out of 5 times). I will turn over and over but get absolutely no signs of firing up (doesn't even stutter). The battery inevitably weakens, so I have to give up. I then go back to it 30 minutes later, and it starts up as if nothing was wrong! I used to get a smell of fuel, so I checked under the car and noticed a leak around the fuel filter, so last weekend I swapped this for a new item, and tightened the hose clips around the pipes to it (I need to get some proper fuel hose clips). I also changed the fuel pump relay. Since then the car has been fine all week, and then today... same problem! I did not smell any fuel today though, so maybe what I smelt before was the leak from the filter. One thing I have noticed is that I do not hear the fuel pump priming. With the MK2 (both 8v and 16v) the fuel pump made a very audible whirr when you turned the ignition on. With the Corrado, I sometimes hear a relay click at the back of the car when I turn the ignition on, (so I guess the fuel pump relay is working) but no priming sound - even when it starts up okay. I always thought that this was normal on the Corrado (i.e. the priming was very quiet) but maybe this is not the case?! Other details that may be relevant... The car does have a factory immobiliser, and I have had problems in the past, but the symptoms are different - i.e. the car fires up and dies again. Also factory immobiliser problems tend to be more consistent There is also an aftermarket Cat1 alarm fitted - a Laserline 996 v2... it is quite old, but the immobiliser usually disables the ignition... the car doesn't seem to have any problems here - I get the ignition on fine, it just won't fire up! Is it possible it has a dual circuit that disables the fuel pump as well? Where would I even begin to find out?? I am seriously considering just sticking the Corrado in the lockup over winter and getting a cheap daily hack, especially with the outrageous insurance renewal. Quote Share this post Link to post Share on other sites
fla 9 Posted October 12, 2011 is the fpr ok? Also, fuel pump relay (167) alright? Is the fuel pressure to the rail ok too - i say this because you mentioned the lack of fuel smell? Quote Share this post Link to post Share on other sites
Kevin Bacon 5 Posted October 12, 2011 Sounds like classic Crank sensor failing. Next time it does it, keep a spare spark plug handy and pop it into one of your HT Leads and rest it on a metal part of the engine. When cranking over, if there's no spark, you definitely have no crank signal. The fuel pump in the Corrado is practically silent. You have to listen very carefully, but the pump is easy enough to test. Undo the fuel rail supply hose and pop it into a container. Take out relay 167 and make up a short wire with 2 male spades on it. Bridge the contacts in the fuseboard (the 2 big ones) and observe the container filling with fuel. Failing either of those two, it's possibly your laserline immobiliser as they always cut into the fuel pump supply wire and starter motor, but sometimes just the one of the circuits fails, which happened to me on a POS Clifford alarm some years ago. Quote Share this post Link to post Share on other sites
Dox 23 Posted October 12, 2011 Try unplugging the crank sensor, check its condition and replug if all looks ok. Faulty crank sensor will have no spark and no fuel injected. Do you have a spare key to try? Ignition switch is another possibility try wiggling the key or take it out and reinsert it. Quote Share this post Link to post Share on other sites
Kevin Bacon 5 Posted October 12, 2011 I hate to say "I said that already", but I said that already. There's nothing you can do with crank sensors, other than remove it from the block and check for a build up of metallic particles which can dilute the signal. You can also put meter across pins 1 and 2 and wave a piece of steel in front of it (no more than 1mm gap though) and see how strong the voltage spike is. Quote Share this post Link to post Share on other sites
tony_ack 0 Posted October 12, 2011 Thanks for the advice... the car is at my parents in Bury as I'm staying there while working in Manchester. Hopefully it will start later today so I can get home! Really do hope it is the crank sensor as it doesn't sound like it's too bad to replace. For the worst case nightmare scenario, it would be the immobiliser! ---------- Post added at 12:43 PM ---------- Previous post was at 12:31 PM ---------- Out of interest... is it possible to change the sensor without any tools? As a quirk of fate, the site I'm working at is within walking distance of a GSF branch, so I could go and pick up a replacement. The problem is that I don't think my dad has any tools at home... I will try and get my dad to test the spark while I'm at work as I prefer not to throw money at a problem without proper diagnosis (he used to be a mechanic so maybe has some spare plugs lying around...) Quote Share this post Link to post Share on other sites
fla 9 Posted October 12, 2011 just need an allen key 5mm or 6mm cant quite remember. Quote Share this post Link to post Share on other sites
tony_ack 0 Posted October 12, 2011 Well, my dad didn't test the spark, but he got it started in the end. The battery was flat when he tried, so he had to jump off another car. It ran for a a few seconds, then cut out and died. When he tried to start again the starter span freely - my dad said there was no compression (to be fair this happened to me once last week, I just assumed it was a dodgy starter!). It finally spluttered into life on a couple of cylinders, then the other cylinders came in one by one until the engine was running fine again. He thinks the problem was that the tappets were stuck open, and that it usually indicates that too thick an oil is being used? He used to be a mechanic so knows a fair bit about these things! It's currently on the Titan Pro S 10w50, which I put in a few weeks ago. Obviously this is on top of the underlying starting issue. As you would expect, the car has behaved impeccably since then, so no chance for further diagnosis! Quote Share this post Link to post Share on other sites
chrisspencer 10 Posted October 25, 2011 Might sound a daft question.. but where abouts is the crack sensor on the block? Cheers Chris Quote Share this post Link to post Share on other sites
fla 9 Posted October 25, 2011 looking from the front of the car, under the middle of the bumper about 4 inches from the base of the block you'll see a black cylinder about the size of a thumb sticking out. It will have a lead with a yellow collar on it. Its held in place with a 5mm allen bolt. Quote Share this post Link to post Share on other sites
chrisspencer 10 Posted October 26, 2011 Thats great, thanks!! Quote Share this post Link to post Share on other sites
poll250 0 Posted November 8, 2011 looking from the front of the car, under the middle of the bumper about 4 inches from the base of the block you'll see a black cylinder about the size of a thumb sticking out. It will have a lead with a yellow collar on it. Its held in place with a 5mm allen bolt. I thought that was a Knock Sensor? Isn't the Crank sensor on the side of the head at the end of the rear cam? Quote Share this post Link to post Share on other sites
Kevin Bacon 5 Posted November 8, 2011 No that's the cam sensor mate. The front of the block has knock and crank sensors and the rear of the block has just the one knock sensor. Quote Share this post Link to post Share on other sites
