| Author | Message | ||
| ctk (Ctk)
New member Username: Ctk Post Number: 42 Registered: 7-2001 |
Doesn't look like you have a check valve. The nut on the fuel line is the locking piece. Have you done your fuel system pressure test? A leakdown test will confirm if poor hot start is caused by a drop in system pressure. | ||
| Greg Rodgers (Joechristmas)
Junior Member Username: Joechristmas Post Number: 142 Registered: 3-2001 |
Is this the check valve on my fuel pump?  | ||
| ctk (Ctk)
New member Username: Ctk Post Number: 41 Registered: 7-2001 |
BOSCH FUEL PUMP Original 308 Bosch Part No. 0580 254 942 Generic Bosch Part No. 0580 254 910 (not 100 as stated in my earlier post, sorry for lapse). | ||
| ctk (Ctk)
New member Username: Ctk Post Number: 39 Registered: 7-2001 |
The 308 has a pre-filter in the primary fuel tank. It is screwed into the tank and can be unscrewed and inspected. Be careful not to collapse the tank when unscrewing! The filter is often caked with goop or has the mesh collapsed with old age. The in-tank boost pump trick is used by Porsche as well. It can be seen in their turbo engine versions but I think most in-tank pumps are installed as a result of fuel tank design and used to prevent fuel starvation situations. If you compare pump pressure between a K-Jet and L-Jat or Motronic system, the K-Jet has higher pumping pressures. If you hear a continuous 'sizzling' type of sound from your fuel pump when hot, you know that the bearings are 'on their way out'. | ||
| ctk (Ctk)
New member Username: Ctk Post Number: 38 Registered: 7-2001 |
The pump does not need to be primed as Edward says. Bosch does recommend however that the fuel filter is primed when replaced. The 75psi pressure of a typical K-jet pump shooting fuel into a dry fuel filter canister can tear the delicate paper filter. Fill it with a little fresh fuel prior to hooking it back on. Filters are also generic with fittings that are screwed on. You have to choose fittings that match your car's fuel hose fittings. Some 308s use twin filters some one large single. I use a large body MB car unit. When checking your pump/filter always inspect fuel lines for kniks or crimps. The diameter of the hose is small but matched to the flow characteristics of the engine. A crimped hose can increase pressure but reduce flow enough to cause false readings and make you go crazy trying to tune your FI. | ||
| BretM (Bretm)
Intermediate Member Username: Bretm Post Number: 1896 Registered: 2-2001 |
Sounds good. | ||
| Edward Gault (Irfgt)
Member Username: Irfgt Post Number: 890 Registered: 2-2001 |
The Ferrari pump is fed by gravity so priming is not necessary. Most new pumps are filled with a light oil for shipping and start up. BMW uses a boost pump inside their fuel tanks on a lot of their cars to feed the main pump. If the boost pump fails the main pump will fail soon after due to starvation. It pumps well but has low suction. | ||
| BretM (Bretm)
Intermediate Member Username: Bretm Post Number: 1883 Registered: 2-2001 |
Hey ctk, when putting the whole fuel system together again is it good to fill it with fuel while bolting it all up? My fuel pump is drained now, when I go to put it together it is the first thing inline from the tank, but it wouldn't be primed at all so until fuel got in it, it would be dry. I'm assuming this would be alright, but just wanted to get a heads up. | ||
| Greg Rodgers (Joechristmas)
Junior Member Username: Joechristmas Post Number: 137 Registered: 3-2001 |
Thanks Ed, I would greatly appreciate it. | ||
| Edward Gault (Irfgt)
Member Username: Irfgt Post Number: 888 Registered: 2-2001 |
Again it depends on the application. You can unscrew the old one from the outlet end and take it to a Volvo or MB store and match it up. There is only an outlet. I will take a picture of one tomorrow and post it. | ||
| Greg Rodgers (Joechristmas)
Junior Member Username: Joechristmas Post Number: 133 Registered: 3-2001 |
Great I will get a new check valve and try that. Thanks for the tip. Is it a generic piece? Does it have one on the inlet and one on the outlet? Thanks Again. | ||
| Edward Gault (Irfgt)
Member Username: Irfgt Post Number: 880 Registered: 2-2001 |
I might want to add that if your pump suffers from a fuel pressure leak down but has no other issues, you can simply replace the outlet check valve for only a few bucks without replacing the entire pump. I do this quite often on a hard to start hot condition. | ||
| ctk (Ctk)
New member Username: Ctk Post Number: 37 Registered: 7-2001 |
If you buy a new pump with a built-in check valve you won't see it. The central post (for fuel and threaded)will be longer than a generic version. The screw-on check valve looks like a large version of a nut (it is a one-way valve, spring loaded ball bearing). BTW, the pump is cooled via fuel running through the entire internal assembly. Run the pump without fuel for more than a few seconds and you get to hear a grinding noise, that tells you that you have just destroyed the pump. Use it further and it will seize (a loud buzzing sound from the pump when it is running is a bad sign!). I think the pump flow test requires it to flow 750cc of fuel a second. Fuel and sparks don't mix! Be careful. | ||
| Greg Rodgers (Joechristmas)
Junior Member Username: Joechristmas Post Number: 132 Registered: 3-2001 |
Thanks for the info. Is the check valve in front of the fuel pump? What does it look like? Is it seperate from the pump? | ||
| ctk (Ctk)
New member Username: Ctk Post Number: 36 Registered: 7-2001 |
The fuel pump on a K-Jet type system is a common user part. The only differences between the Bosch p/n are to signify the fuel line fittings provided for the part and the type of car using it. These fittings can be bought separately and screwed on the central post. Make sure you get the check valve fitting as well. Latest pumps have check valve built inside and cost more. Because it is a continuous flow system, the pump either works or doesn't. The flow rate of the pump is important. There aren't many versions but the largest flow capacity versions were made for the MB 450SEL 6.9 and Porsche 911 SC Turbo. Racing versions had black painted bodies and their electrical posts screws were a completely different size. BEST NEWS. Bosch has a generic part no. for the pump, it ends with 100 which is the basic pump assembly without check valve and fuel end fittings. This is the same pump that a 308 uses although the F-car part number and the equivalent Bosch p/n are specific. The 100 pump costs about US$55/-. | ||
| Steve Magnusson (91tr)
Member Username: 91tr Post Number: 569 Registered: 1-2001 |
Greg -- you might try seeing if you can read the Bosch PN (stamped?) on the pump itself -- usually has the format: N NNN NNN NNN My local "Bosch" Import Auto Store doesn't show Fs typically in their application guides, but if I bring in the Bosch number they've been able to match it (although on my last couple of Bosch things the discount F part suppliers were actually a few dollars cheaper). | ||
| Greg Rodgers (Joechristmas)
Junior Member Username: Joechristmas Post Number: 131 Registered: 3-2001 |
I was curious to know about the Bosch fuel pump on a QV. Is it a Ferrari specific part made by Bosch or does it fit a Volvo, Mercedes too? I checked the price and it was $270 for a new fuel pump. I would think that another car would use the same fuel pump and it would be more reasonable. |