Identical cold start everyday

[4pullingGM]

You might also want to try cycling the key a couple of times before you try to start the engine. If something is bleeding down fuel pressure this should build build it back up enough so that it will start normally. Doesnt fix the problem persay, but it masks the symptom.

 

[Adams95]

well it looks like this has caused a whole new nightmare...today on the drive home from work, i was stuck in traffic for awhile. When i went to give it gas, it had no power and barely made it up this hill on the freeway at 40 mph, from there I made it to about 55mph but everytime i pressed the throttle to a certain point, the truck would shutter. Well this kept getting worse and worse until i was going 15 mph and had to pull over on the side of the road. I let it sit for about 5 minutes, started up just fine and started driving. I made it about 2 miles before i was on the side of the road again. Let it sit for about 15 minutes, pulled my codes from the CEL i got. 172 and 176, Left and right banks too lean.

After I reset the computer, i was letting it run for a few in the parking lot I noticed it was about to die at 500rpm, but then recovered...I got in the truck and rev'd it...it sounded healthy. I was able to limp it home and it only shuttered slightly, but was able to keep going. It almost seemed like if I took a bump it fixed or made worse the problem.

What do you guys think this is? I changed the oil yesterday, and then I drove around and did errands for about an hour with no problem in the 108 degree heat. But today I drive to work and i notice shes running a little rough, however I make it to work fine. It was driving home and sitting in traffic where she got angry.

 

[Adams95]

I just read the other posts you guys made as well and the fuel filter was changed about 2 months ago or 5,000 miles. I dont have access to a fuel pressure gauge, but I can try to get one tomorrow.

 

[Adams95]

So it's been a tough time for me lately, due to the fact I just started a new job my $$ fund is not so hot and the fuel pressure tester is gonna have to wait till thursday.

However here's an update of the problem...My friend thought it was the TPS (voltage readings were coming in a bit high), so he bought one from autozone, we swapped it in...now the truck runs even more lean. The only way to truely test is to drive home from work when its 110 degrees outside. When I tried to drive it home...it was pissed. Usually when it keeps losing more and more power, when i shut it off for 5 minutes it'll start right up and be drivable for a little bit. However this time when the truck died, it flat out would not start back up. I had to go back to the truck 3 hours later and limp it home.

Some things to note:
1. When you start up the truck it revs upto 2k and slowly drops down to 1k, but once warmed up will hunt between 800-1100 rpm.
2. When it died yesterday it seemed like the fuel pump, because it didn't just die, it stumbled all the way down and then wouldn't start back up.
3. If it was a vacuum leak from the intake, could it keep it from starting after it died? and would it show the same systems?
4. CEL codes have been as follows:
172
(R,M)
Oxygen sensor not switching - system is or was lean - Single, Right or Rear HO2S - Fuel control

176
(M)
Oxygen sensor not switching - system is or was lean Left or Front HO2S - Fuel control

181
(M)
Fuel system was lean at part throttle Single, Right or Rear HO2S - Fuel control

189
(M)
Fuel system was lean at part throttle - Left or Front HO2S - Fuel control


What do you guys think?

 

[ibdranger]

Egr?

Hello.
Here goes my shot:
I have 195,000 on my Ranger, OHV, 95 and have done most all of the work on it thru the years. So I am no ace tuner. I redid my intake gaskets, which relieved the high idle, hunt and peck for an rpm. I also found a hairline crack in the exhaust entry portion of the EGR. The pipe thread portion of the EGR had the very small leak, and would let the exhaust pipe give odd readings to the ECM. So those were my cures for a similar problem.
I would be REALLY curious to see if your egr system is opening and staying all or part way open. My understanding of this system is that it should not be in operation at idle or WOT. If it is stuck open, or partially open, it is almost impossible to start. Or idle smoothly. It might explain lean codes on both banks? I really think that this sounds like your best shot at explaining your motor. At idle the motor should have no vacuum at the egr, and the egr should be closed.
Hope this helps.

 

[Adams95]

ranger, thank you for your advice. I've never tinkered with an EGR system before, but that thought of it malfunctioning has been in the back of my head. However last night, I might of got some good news (finally).
The truck wouldn't even start last night and when i turned the key to run I couldn't even hear the fuel pump going for 2 seconds. I took a screwdriver and let the pressure out of the schrader valve, but only a pathetic little amount came out of the valve (looked like 2 psi to me lol).

I noticed the check engine light was flashing and so I got the code from it just by running the KOEO (it also showed up in the CM), the code was: 542 - Fuel pump circuit open...Now i know this could also mean the fuel pump is just straight up dead, but having some background in low voltage, this is something I don't mind troubleshooting. I also noticed on the inertia switch that the wiring harness that plugs into the switch appears to be plugged in, but the top clamp that securely connects it is broken off...Do you guys think this is cause for alarm?

I have a few questions on how exactly to test...
1. How do i test continuity for the inertia switch? Just backprobing the electrical connector?

2. With the connector right before the fuel tank, is red and black the only wires i need to test and look for 12v?

Thanks as always guys, everyone's been a huge help on here

 

[DR_APLET]

reading through the posts, a couple things come to mind, first sounds like you have located a fuel pump issue which could explain the progressive deterioration of fuel delivery. use a can of starting fluid once you get it running again, and spray the intake and vacuum lines and listen for a change in RPM, i dont think there is a gasket issue.
secondly have you checked your catalytic converter you may have a restriction there.
thirdly the temperature seems too low, usually mine runs almost half on a mild day but on a hot day you should see half or just above. you engine is not heating to operating temperatures therefore dumping way more fuel in the system than needed check the thermostat to see if it has been drilled or the check valve removed.

 

[Adams95]

Thanks for the response DR, I've went through the engine about 5 times spraying it with carb cleaner, looking for a vacuum leak. However not once have I heard the idle change.

How can i check to make sure the cat isn't clogged? Could I just hook my vacuum gauge to the brake booster line and make sure it's getting adquate pressure?

 

[Adams95]

So the saga continues...

Last night I ran a jumper wire from the positive battery post to the PK/BK wire leading from the inertia switch to the fuel pump. The result was that the fuel pump started running!

Now with the jumper out, I metered the DG/Y wire coming into the inertia switch, it came back with 6v (temp outside 85 deg). Oddly enough I metered that same wire this afternoon (temp outside = 110 deg) and it only had 1.75v.

I've checked all 3 relays in the PDB and they appear to be working fine. So I believe I'm losing voltage either at the PCM or the PDB. I pulled the PDB open last night and it looked like all the wires were perfectly fine. I also sprayed the entire top of the box down with electrical contact cleaner. I've also checked continuity at all the fuses and all seem fine, but i have not checked voltage yet.

I guess the only things left are checking voltage at the PCM? Or could a bad ground cause all these issues?

 

[DR_APLET]

a bad ground could cause some erroneous issues Foxracin had a starter issue because a bad ground, but it would seem that it would have to be so isolated it would be hard to find. check everything back to a clean chassis.

as for checking the cat you could check the Exhaust gas return or the O2 sensor with a pressure gauge i know that my brother melted his and the pressure gauge nearly blew out when it was put on the 02 port.

another question i had does your fuel gauge work? when you turn the key on had the fuel pump working then not and when jumper-ed it works?

 

[Adams95]

another question i had does your fuel gauge work? when you turn the key on had the fuel pump working then not and when jumper-ed it works?

I'm gonna assume you meant fuel pump instead of gauge. Well the other night i tried to start the truck and i got a new CEL, it was code 542. Open circuit, so since then the truck wont even start. I noticed you couldnt hear the fuel pump turn on, so now the only way the fuel pump will turn on is if the jumper is connected to the PK/BK wire.

 

[2000StreetRod]

Fuel pump circuit

The PCM monitors the voltage at the fuel pump relay via the dk grn/yel wire that also goes to the inertia fuel shut-off switch. The voltages you read were probably from the input of the PCM and not the output of the fuel pump relay which was open.

If the Check Engine light comes on when the ignition switch is in Run then the PCM has power. The relay is energized when ignition is in Run or Start via fuse 19 and the power diode. When the PCM power relay is energized power comes from Fuse link 13 which is hot at all times.

Code 542 indicates that the power is not flowing from Maxi fuse 3 thru the fuel pump relay to the inertia fuel shut-off switch. Have you tried swapping the fuel pump relay with another relay? On my 2000 Sport the rear wiper up and down relays are identical to the fuel pump relay.

 

[Adams95]

I have swapped relays with no different result so far. The CEL does come on with the key in the run position so i know the PCM is okay.

 

[budwich]

can you review your "timeline"??? did you get the code before or after you jumpered past the inertia switch?

 

[budwich]

As discussed, the reason for the "low voltage" (ie. 6) is that you were reading a "no relay operated condition" which was basically the voltage "floating inside the PCM monitoring circuit"... what's strange was the 1.75v measurement... hence my previous question.

 

[Adams95]

So turns out my meter was screwed up...my friend brought over his meter and i successfully tested 12v all the way back to the connector next to the gas tank. Looks like fuel pump is straight up dead....
Timeline:

Truck starts acting up in hot temps:
codes:
172, 176

Next day same thing happens:
181, 189

Next day, can't start truck:
542

Last night, jumped inertia switch, fuel pump turned on

Today:
Found out fuel pump is

 

[DR_APLET]

great, dead pump, which is where i was going in my mind. i remember that there is a cut off switch which which kills the ignition when either the fuel runs low or it thinks the fuel has run low, which prompted my question on the fuel gauge, thinking back to the pressure switch and float switch. good to hear you have a probable solution.

 

[Adams95]

Just to put an ending on this topic, I finally finished cutting the access hole, changed the fuel pump and....
She runs like a champ, ironically enough it now starts up immediately! and has more power (as much as possible for a 4.0 ohv)...Now I know the TPS was also bad and that could be combined with changing the fuel pump for the way she runs...Things are looking up for my lil explorer