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Hard to Start Problem with a Volvo 264. |
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One day in 1987, a Volvo owner drove into my workshop in a 264, V6. It was a bad day for him to turn up. I was crook as a dog with flu and for some reason I ended up baby sitting my 10 month old son. I had him in one of those walking contraptions that he could propel himself all around the office and pull stuff off the walls and generally mess my space up. So in walks this guy, cautiously I might add, having a good look around in the workshop as he walked in. He asked if I could fix his car. Without hesitation I of course said yes and he replied “I’d like to see that because I’ve had two dealers look at it costing me $2000 each and it still does the same thing”. Gee I wish I was not so crook, I might have shown some enthusiasm at getting a chance to solve his problem. My first question obviously was “what is it doing?”. He explained that when he has been shopping or on any sort of trip, when he returns to the vehicle to start it after only about 5 to 10 minutes of sitting, the engine takes a long time to start. That was it, his only complaint. He stood there and by the looks he was giving me I think he expected me to fix it straight away. I really was not up to it and then my young fella found some parts hanging on the wall that took his interest and proceeds to rip them of the pegs, just great, all I needed. I sorted him out and restricted his area of movement and then asked the customer nicely if he would like me to look at it right now. I was hoping like hell, he could see I was not looking to flash, but I guess he didn’t notice. So out I went with him in toe, I could tell he was not going to go away and let me fix it in peace so I had a pair of eyes looking over everything I did, which in the end wasn’t much. He told me that it had a new ignition module fitted at one dealer and the other replaced the fuel distributor. These were replaced to fix his problem, he was told. I tried to start the engine and as he stated the mother was really hard to start, but once it did, it ran very smoothly. That was my first clue, I ruled out vacuum leaks straight away without even using my ultra-sonic leak detector. This is because any vacuum leaks in a CIS system will cause poor idle quality as well. I ruled out ignition simply because it just had a new module fitted, if the fuel pressure test passed then I would come back to Spark later. The first thing I was interested in was the fuel pressure readings. It just so happens it is the first letter of the acronym F.A.C.T.S. This article is in the Tuning section. So I connected the fuel pressure gauge up to the top of the fuel distributor and took some readings. The system pressure was perfect, the control pressure was within specs but the rest pressure was not good. The rest pressure disappeared in about 20 secs. AH HA I declared to the customer, I have found your problem. He was in total disbelief that I claimed to have found the problem so quickly. I took him over to my Bosch CIS wall chart and showed him where the problem was. I showed him the illustration of the small ‘O’ ring on the end of the pressure relief valve plunger that seals off the return line back to the tank when the engine is shut down. By sealing off the return, the fuel accumulator then maintains constant rest pressure for about 15 or so minutes. This was not happening. The explanation as to why is in the schematic descriptions. I showed him there was no other conclusion to draw and even he could see this from the illustration. These Bosch charts are fantastic customer aides. The ‘O’ ring I had in stock, $20 bucks for my time and I should have a happy customer. I fitted the part and confirmed that rest pressure was now good. Once I started it, he wanted to take it for a drive and then come back and let the engine sit for five minutes. If it started as it should he would pay me if it didn’t I guess my name would be mud. When he came back I was half dead and my son was getting tied and needed some sleep, which is what I needed as well. We waited five minutes and I am happy to say the engine started straight away. Well didn’t his attitude change, I was suddenly THE MAN. He then booked the car in for a full service and tune and other repairs that he wanted done. The whole process only took one hour, I could have done it in 20 minutes if I was alert and healthy. This guy must have a lot of friends who own posh cars because within weeks I started to get an influx of Volvo's, Mercedes and other European makes, all of which had Bosch CIS systems. There you go, something so simple, and yet it was not detected. The mechanics missed the basic fundamentals of CIS injection. It is clear that no one tested the fuel pressure so how anyone determined that the ignition module or the fuel distributor were at fault has got me. The Bosch CIS system is the easiest system to diagnose, all that is required is a CIS fuel pressure gauge. Beyond that there is more equipment available to test more deeply and with the aide of an oscilliscope and exhaust analyser the whole system, ignition and fuel can be tested and adjusted. This story was not about making me look good, because I did nothing exceptional. It is about looking at basics and doing the basic tests to find the cause of the problem, there was no rocket science in this one. Hope you enjoyed the read and I didn't bore you to much. |