Fuel pump prime

[talonDSMerr]

I recently installed an AFPR, sending/return lines, injectors, and a walbro 255. Also just rewired the pump.

When I turn the key to acc., I don't hear the pump prime for several seconds. As a result, it takes a couple cranks for the fuel pump to rebuild pressure in the lines before the car starts. I did a search on the topic and it seems 1g's are supposed to prime with the key turned to acc, while 2g's are split... What might cause this? Thanks for input.

Also, due to the fact the 255 pump is used, I'm suspicious my fuel pump o-ring might be worn, letting pressure bleed out of the lines. But I'm not sure why the pump does not prime with the key turned to acc.

 

[habitatguy187]

Wiseman Steve said that the fuel pump doesn't prime until you start cranking the car. Will the car eventually start if you keep cranking?

 

[talonDSMerr]

Ok, that clears it up then. Yes car starts after 2-3 cranks. I'll have to check my fuel pressure gauge and see if pressure is dropping overnight.

 

[nightracer91]

Some AFPR's loose pressure after shut off, my EBAY one does but it does the job so I can't complain. Yea 1G's don't run the pump until the car is cranked, it should still start on the first crank it just may take a second.

 

[91tizzy]

My setup does the same thing since my afpr install....(was having bad overrun issues and do not actually know what pump is in the car) but I dont hold pressure in the system after shutoff (not an el cheapo regulator either its a Fuelab kit from STM). Wondering if its the pump ring myself. Any wisemen chime in as to why this causes this?

 

[Boosted98gsx]

Fuel pump won't start until your cam angle sensor starts spinning unless you have a management system.

 

[turboglenn]

Some AFPR's loose pressure after shut off, my EBAY one does but it does the job so I can't complain. Yea 1G's don't run the pump until the car is cranked, it should still start on the first crank it just may take a second.

Aeromotive AFPR's are famous for this, they will bleed down pressure in a heart beat. Although i was under the assumption that 2g cars did NOT prime while 1g cars did.. I could be wrong but i thought i remebered hearing it that way.. I know 2g's dont because i've worked on so many

 

[the_mork]

Double check that you didn't tear the o-ring at the pump. If you rolled or tore that seal then fuel will flow back into you gas tank instead of staying in the lines and cause you to have a slow cold start. Warm starts should be normal.

 

[talonDSMerr]

Yep, that is probably the culprit. Either that, or my Fuelab AFPR lets pressure bleed out. I was almost positive I did that o-ring/seal correct, lubed it with oil and slid right in. That is something I will have to check or just replace the seal altogether next time the pump assembly is out.

Turboglenn, I thought the same about 1g's priming with acc. and 2g's not. DSMLink has an option to turn the pump on, so I might try that option.

 

[toofast82]

Turboglenn, I thought the same about 1g's priming with acc. and 2g's not.

1g's definitely do not prime with the key to "on"

 

[turboglenn]

1g's definitely do not prime with the key to "on"

Thanks for clearing that up. I haven't got indepth enough to the factory ECU and it's behacvior in a 1g in a LONG time. As is part of my business, i usually rip them out and replace with a new harness and aftermarket ECU (HAltech) and they all prime on pre-start and post stall conditions

 

[toofast82]

Yeah, you would think they would like 90% of the rest of the cars, but sure they had a reason