| Author |
Message |
Phil Bryson (Phildo)
New member
Username: Phildo
Post Number: 30
Registered: 8-2002
| | Posted on Tuesday, October 29, 2002 - 1:09 pm: | |
Larry,
People like you are the reason this site is so great! I currently have the vehicle at my mechanics having some suspension work done - thus the delay in my testing the things mentioned in this thread. I hope to get the car back next week.
Thank you very much for you offer of help.
Regards,
phil |
Larry Fletcher (Fletch62)
New member
Username: Fletch62
Post Number: 4
Registered: 6-2002
| | Posted on Sunday, October 27, 2002 - 8:04 pm: | |
My buisness is rebuilding Bosch CIS fuel distributors. The problems you are having are caused from fuel pressure leaking down. During cold start, the cold start valve provides extra fuel to run the engine until the fuel system is up to pressure. During hot start the cold start valve does not spray and you have to keep cranking the engine to run the fuel pump until the system is up to pressure. Pumping the accelorator does nothing more than open and close the throtle valve, this system has no accelorator pump like carbs do. There are several places that you could be leaking fuel pressure, some are in the fuel distributor itself, and some are not. I provide a lot of tech support for the CIS injection systems and feel like I can talk you through the tests needed to solve your problem. I also can test your Fuel Distributor and tell you if that is your problem. You can call me at 225-273-0331, this is home, office, and tech support.
Thank You
Larry Fletcher
CIS Flow Tech, LLC. |
BretM (Bretm)
Advanced Member
Username: Bretm
Post Number: 2777
Registered: 2-2001
| | Posted on Wednesday, October 23, 2002 - 8:38 pm: | |
That was my reason and how I found it out when I had the same problem. |
Tom Bakowsky (Tbakowsky)
New member
Username: Tbakowsky
Post Number: 21
Registered: 9-2002
| | Posted on Wednesday, October 23, 2002 - 7:12 pm: | |
Do this..Go under the car were the fuel pump is,and beside the fuel pump is the fuel accumulator. You will see 2 lines with fittings on the rear and one line that is held on by a hose clamp at the front. Start the car and let it run for a few minutes then shut it off. Undo the line that is held on by the hose clamp and pull off the hose. If any fuel comes out of the accumulator, then that is your hot start problem... |
Greg Rodgers (Joechristmas)
Member
Username: Joechristmas
Post Number: 503
Registered: 3-2001
| | Posted on Monday, October 21, 2002 - 10:23 am: | |
My QV fires instantly when warm even in the heat of the summer. I had this problem before and I replaced the check valve, externally as stock the check valve is in the pump. It works great now. It shouldn't have this problem so don't believe that it is normal. For the carbs cars to take a few seconds after warm, with a time period of sitting it happens but nothing for a long period. The carb cars don't have the pressure being maintained in the system either and the operating pressure is around 5 psi. The FI cars have the check valve and the accum. It could be possible that your mixture is off as well. |
Lawrence Coppari (Lawrence)
Member
Username: Lawrence
Post Number: 325
Registered: 4-2002
| | Posted on Monday, October 21, 2002 - 5:57 am: | |
You could be losing fuel pressure. When that happens, you get vapor lock more readily because fuel boils at lower temperature. A loss of fuel pressure is due to a leak somewhere in your injection system.
The system on my 328 is Bosch CIS. It is nearly identical to that used in my old Mercedes. The MB would not start easily if I let it sit when hot for a few minutes. It always started when cold. On mine, the problem was a leaking fuel accumulator allowing the pressure to drop. System should maintain fuel pressure even when engine is off. If it does not, you will have a problem starting it. Mine was not vapor locking because it would be hard starting even in the winter with the hood open. The low pressure makes starting difficult.
My two cents. |
John Bicsak (Funshipone)
Junior Member
Username: Funshipone
Post Number: 140
Registered: 1-2002
| | Posted on Sunday, October 20, 2002 - 8:20 pm: | |
When I first bought my 1984 308 QV had same problem under warrenty dealer replaced what he called cold start valve no more problems. |
Mark Eberhardt (Me_k)
Junior Member
Username: Me_k
Post Number: 142
Registered: 5-2002
| | Posted on Saturday, October 19, 2002 - 9:22 pm: | |
Yeah, could be flooding. Does holding the pedal down work better than pumping? Pumping should shoot more gas in. |
david handa (Davehanda)
Member
Username: Davehanda
Post Number: 269
Registered: 5-2001
| | Posted on Saturday, October 19, 2002 - 8:29 pm: | |
I agree, (though not a mechanic) it sure sounds like flooding. Might also check that the injectors are not leaking as well. The reason it starts cold is the gas has all evaporated. Pumping or holding the accelerator down introduces more air? Versus not, and keeping the throttle body closed...just a thought. I think the pressure is not holding and gas is leaking into the combustion cylinders on shutdown.
Of course I could be completely wrong about this. |
Grant Gilmour (Grantgilmour)
New member
Username: Grantgilmour
Post Number: 18
Registered: 8-2002
| | Posted on Saturday, October 19, 2002 - 8:12 pm: | |
Ken, don't believe the old "it's a common problem" line. My 1983 308QV starts just fine no matter how hot it is. Never need to touch the gas either.
PS. Don't adjust the mixture without a CO/hydrocarbon gas analyzer. Been there, screwed it up. |
Bart McMurry (Mcmurb)
New member
Username: Mcmurb
Post Number: 5
Registered: 9-2002
| | Posted on Saturday, October 19, 2002 - 2:28 pm: | |
Phil
My 85 QV has always had the exact problem you describe. Dealer has replaced fuel accumulator/check valve with limited success. In my opinion my car is not starved for gas on warm start but rather flooded since it will eventually start after pumping accelerator. I suspect in my case and maybe yours that there is a faulty cold start injector to blame that is either leaking when i turn off the engine, or the temperature swith is shooting gas into chamber on hot starts when it doesn't need it.
There is curently another post on this topic that has some great ideas for diagnosis. |
Phil Bryson (Phildo)
New member
Username: Phildo
Post Number: 24
Registered: 8-2002
| | Posted on Saturday, October 19, 2002 - 12:19 pm: | |
Thank you gents. I was under the impression that one shouldn't pump the throttle of an injected car - don't know why, but seems like I heard that at one point long ago. Of course, that doesn't mean it's accurate.
I had the car inspected, but am having my own mechanic go over it next week. If I learn anything, I'll post it. |
Mark Eberhardt (Me_k)
Junior Member
Username: Me_k
Post Number: 135
Registered: 5-2002
| | Posted on Saturday, October 19, 2002 - 9:17 am: | |
It is not normal to have trouble starting your car. On an injected car the fuel pressure is so high vapor lock should not be posible. The pressure causes any vapor that might have formed to condense as soon as the pump come on (remember bioling point is temp @ a pressure). If pumping the throtle helps, it sounds like it's just to lean and your going to need to go through the mixture adjustments in the service manual. |
Bruno (Originalsinner)
Member
Username: Originalsinner
Post Number: 659
Registered: 5-2002
| | Posted on Saturday, October 19, 2002 - 9:04 am: | |
It is annoying |
Ken Ross (Kdross)
Junior Member
Username: Kdross
Post Number: 158
Registered: 2-2002
| | Posted on Friday, October 18, 2002 - 9:09 pm: | |
My 1985 308 QV does the same thing. My mechanic told me that the cars run so hot (fuel vaporizes) that it is a common problem. I find that if I pump the gas a few times, start the car as I continue to pump the gas, that the car starts just fine. Sometimes it takes a lot of pumping. |
Brian stewart (Eurocardoc)
Member
Username: Eurocardoc
Post Number: 390
Registered: 11-2001
| | Posted on Friday, October 18, 2002 - 2:43 pm: | |
losing fuelpressure, either the check valve on the pump or the seals at the pressure relief valve. See archives. |
Phil Bryson (Phildo)
New member
Username: Phildo
Post Number: 23
Registered: 8-2002
| | Posted on Friday, October 18, 2002 - 2:03 pm: | |
I have recently acquired my first F-car, an 85 308QV. Are these cars sensitive to vapor lock? I have experienced a few times that after driving, if I shut it down briefly (i.e. fill with gas, run into a store) they car won�t start. It�s trying hard, but won�t kick over. After waiting 10-15 minutes, it fires right up. It will start with a compression start. Always fires up fine if cold.
Any advice would be most welcome.
Thank you,
phil |