Fuel pressure specs for 2000 Rodeo 3.2L

[terryd513]

Seasons greetings to all, does anybody know/have the factory fuel pressure specs for a 2000 Rodeo 3.2 V6. I'm trying to rule out the fuel regulator on a cold start issue. The vehicle currently runs 35 Psi at idle and peaks at 43 Psi at idle with fuel regulator vacuum line removed/plugged. Pump pulls 75 Psi with return line momentarily pinched. Also, fuel system does not hold pressure, bleeds down when engine is shut off? Is this normal for Isuzu's? I'm having to hold the accelerator pedal down on cold start, engine pops/backfires through thottle body but starts, otherwise will not start easily when cold. engine starts fine hot? Is this possibly a cracked intake manifold gasket issue? Any input/advice you could give is greatly appreciated, thanks Terry

[amigo-2k]

what happens if you turn the key to the On postion, wait 10 seconds and then try to start it?

[terryd513]

Originally Posted by amigo-2k

what happens if you turn the key to the On postion, wait 10 seconds and then try to start it?

Ryan, thanks for the reply. I have never tried that. What's it do?

[amigo-2k]

It allows the fuel pump to pressurize the system.

Right now when my truck is cold, if I don't do this is stumbles a bit at start up.

[terryd513]

Originally Posted by amigo-2k

It allows the fuel pump to pressurize the system.

Right now when my truck is cold, if I don't do this is stumbles a bit at start up.

Ryan,

Hey, some success, thanks for the info..I tried waiting 10 seconds before starting cold, I heard the buzzing of the pump and then a click of a relay or switch under the hood. The car fired right up, wow, no stumbling or anything...will try starting cold again several times again this weekend to verify. It looks as though you may be on to something. The question is what causing the fuel pressure lag, a weak fuel pump, leaky regulator? Does your fuel system maintain pressure after engine shut down? Do Isuzu's have a check valve in the fuel fump outlet to prevent bleed down like other GM/Ford/Dodge FI vehicles? My fuel systems pressure bleeds down to zero Psi within a minute of shutdown. Again, thanks for your input, Happy new year..Terry

[amigo-2k]

During the Summer I can just turn the key and go, 8 times out of 10 it will not stumble. But I'm so use to key On buzz, relay click, and start it up, that I rarely just turn the key and go any more.

Mine has done this since new.

good info in the FAQ's on this too:

http://isuzufaq.ibctech.ca/#faq22

[Ramblin Fever]

Same here.

Don't know how I ended up coming to the conclusion that it started easier after following the same action as Amigo-2K described - but it definitely does.

I typically only have to do this after it's sat for more then 3-4 hrs though, not every time.

[terryd513]

Originally Posted by Ramblin Fever

Same here.

Don't know how I ended up coming to the conclusion that it started easier after following the same action as Amigo-2K described - but it definitely does.

I typically only have to do this after it's sat for more then 3-4 hrs though, not every time.

I ordered a new fuel pump/sender assy $130.00 factory AC/Delco OE part,not $315.00 the dealer wanted! It just arrived this evening. The new pump definately appears to have a check valve on the output side of the pump. You can't blow any air backwards into the pump; ie, this would also stop the system fuel pressure from bleeding down..

I'm pretty sure the culprit is a bad check valve in my current fuel pump, my system won't hold pressure when the engine is shut off. When I install the new pump, we'll know for sure? I'll report back, thanks to all who have replied-Terry

[terryd513]

Originally Posted by terryd513

I ordered a new fuel pump/sender assy $130.00 factory AC/Delco OE part,not $315.00 the dealer wanted! It just arrived this evening. The new pump definately appears to have a check valve on the output side of the pump. You can't blow any air backwards into the pump; ie, this would also stop the system fuel pressure from bleeding down..

I'm pretty sure the culprit is a bad check valve in my current fuel pump, my system won't hold pressure when the engine is shut off. When I install the new pump, we'll know for sure? I'll report back, thanks to all who have replied-Terry

Ryan,

Thanks for your previous replies to my posting. Just thought I'd let you know, the fuel pump internal check valve was the problem. Car is fixed, starts like a champ every time, all the time. My fuel system wasn't holding pressure after shut down, even thought pump made 35 Psi, consequently causing the cold start issues, but oddly no problems warm start? Changed out the pump, sytem now runs 37 Psi and holds pressure indefinately after shut down. Check your vehicle for fuel pressure status after engine shut-down, should hold pressure, otherwise you have same problem. Also, I was able to buy a complete brand new OEM factory AC/DELCO fuel pump/gauge sender assy for $130.00 on EBAY. As you know the dealer gets over $300 for the same part. Search "Isuzu Rodeo fuel pump" on Ebay if interested and the vendor should come up. Again, thanks for your help...Terry