I just replaced my fuel pump, why does this happen?

MilwaukeeV70owner · Post by **MilwaukeeV70owner** » 09 Sep 2010, 19:24

I just had my fuel pump and fuel pressure regulator replaced about a week ago and I've been noticing some unfamiliar things happening after I start the car cold. Once I drive it for a while, everything runs perfectly(starting with a normal crank that is). Here is a video of my car starting cold...

As you can see, it wants to boost the RPMs for some reason. Sometimes, I've seen it do the opposite where it will drop to 0 and the car dies or it will gargle and chugg (and vibrate the steering wheel something fierce) for a while.

I never had this problem b4 the pump and FPR were replaced. I used to turn the car in the ON position for 3 seconds, pull it out, repeat, and start the car.

Should I remove my MAF sensor and try starting it cold to see if it behaves any differently?

BTW, I recently replaced my ETM with one to the XeMODeX Inc ETM's, so we can rule that out.

Post by **Pauloil** » 09 Sep 2010, 19:44

clean the IAC under cover over throttle body

FCPEURO · Post by **FCPEURO** » 09 Sep 2010, 20:10

Sounds like it is not getting enough fuel at startup. If you can get your hands on a fuel pressure gauge, that would tell all.

nightc1 · Post by **nightc1** » 09 Sep 2010, 21:49

Mine did something similar before the fuel relay kicked the bucket. Try removing the relay and put a jumper in it's place and see if the problem goes away. If it does, then there you go... yo ugot a bad (possibly poorly repaired) relay.

MilwaukeeV70owner · Post by **MilwaukeeV70owner** » 12 Sep 2010, 19:51

I used carb cleaner on my IAC and still have the same symptoms. This morning I started it cold and let it settle down for about 60 seconds, and then I pulled out the MAF (the circled component in the picture). It died immediately. Dumb question but, Is that normal or not?

And as far as testing the relay goes, Is this what I should attempt?

https://www.matthewsvolvosite.com/forums ... php?t=9681

MilwaukeeV70owner · Post by **MilwaukeeV70owner** » 18 Sep 2010, 12:06

I still need advice on my problem. Here's what I've attempted so far:

1. Pulled the relay out, and put copper wire to jumper pins 31a and 31b together.

2. B4 starting, pulled out the harness for the MAF sensor, car would start, then shake.

3. After car has started, I pulled the MAF sensor, the car stalls and I hear a ring tone coming from somewhere under the hood

4. Cleaned my IAC with carb cleaner and q-tip

5. Removed battery, bled out any phantom charge by hitting the brakes for a while. re-attached battery to reset itself

Here's whats been happening today when I start the car semi cold (3-5 minutes of driving, got gas, tried to re-start)...

It seems like it has something to do with fuel delivery at startup. Everything seems to operate much better once I drive for a while, but until then, my pedal is SUPER touchy and I smell an indescribable odor. What should I check next?

Post by **pkc303** » 19 Sep 2010, 00:37

See if something crawled up in your motor and died.

Do you have any lights, like maybe a check engine light.

Check the pressure of your fuel rail.

Post by **matthew1** » 19 Sep 2010, 11:05

I'd do two very easy things: I'd have someone rev it while I looked, listened and smelled under the hood. You're trying to find leaks letting in air. Vacuum elbows or lines, anything intake related. That is how I found a large air leak from an intake hose that had popped off during a hard acceleration. I'm not saying your problem is this exactly, but maybe it's a hose and you'll be able to hear it.

But before that, I'd let her sit for an hour or two and come out when she's cold. Turn the key to II, but do not start her. Listen for the fuel pump to energize and pressurize the line. Then go up to the shraeder valve on the fuel rail and with eye protection and a rag and gloves on, see if fuel squirts out.

MilwaukeeV70owner · Post by **MilwaukeeV70owner** » 19 Sep 2010, 17:22

Ok, I'll check the pressure at the shraeder valve tomorrow. I know I've checked it the other day while, but not with the key in position II. Visually, all the intake stuff I can see looks good, but I'm going to keep re-checking it.

I just purchased a new MAF sensor and Fuel pump relay just so I can rule them out. I'll keep you posted.

MilwaukeeV70owner · Post by **MilwaukeeV70owner** » 01 Oct 2010, 04:50

The shraeder valve had plenty of pressure when I released the valve at the fuel rail.

The MAF sensor and fuel pump relay were both replaced, but I don't believe it had any effect. It is still very drivable, I just need to be conscience of not turning it off shortly after starting it cold.

But I want to fix this problem...

As far as vacuum lines go, I do have a CEL that indicates an EVAP system leak(I should have mentioned before), but the guys who dropped my tank to install the fuel pump did a smoke test and told me the installed new hoses by the charcoal canister where they found leaks. The CEL is still there after I disconnected the battery for a while and I don't know where to begin with checking for vacuum leaks.

Any ideas?