4cyl ranger lacks power, hard starting

[scrivyscriv]

My shop manager couldn't even figure this one out.

1996 4cyl Ranger - we just did a transmission filter change, oil change, coolant change, power steering flush, fuel filter replacement, belt replacement, forward O2 sensor replacement, and both radiator hose replacement.

It had codes for a P0144 (not sure if that's the exact code) undefined EGR related and lean condition O2 sensor low voltage. The engine ran much better after changing the O2 sensor. However, when I was almost done servicing the truck, the engine would not crank up. The inertia switch seemed to be part of the problem and we got it to crank up but the engine lacked power - replaced the inertia switch but still the same symptoms. The engine is getting
A) Spark
B) Fuel, and
C) seems to be timed ok - it's making decent compression.

Today we changed all 8 plugs and it cranked up right away but still doesn't have power. I don't have a fuel pressure gauge or a timing light or even a noid light (sheesh... Mac is so expensive...) and we're all pretty much scratching our heads here on it. The owner basically got a free tuneup since the truck was running fine when it got here. But I hate to send it out like this and we've done all we know to do so far.

The plugs were really fouled - seems like it's dumping way too much gas and running rich. But since I've reset the CEL for the O2 and EGR codes I haven't seen any more codes.

Any ideas??:roll:

 

[chance942]

What's the air filter look like?

 

[scrivyscriv]

Left that out of the original post - we changed the air filter too, so it's brand new.

 

[almond900]

might sound silly but do you have all the plug wires on correct? not trying to be a smart ass but I had a trans am come in with a mis-fire and after 3 hours of scratching my head and swearing I checked the firing order and 6 and 8 wires were switched

 

[scrivyscriv]

Ha yeah I've done that on a tuneup before.. Really embarrassing! The wires are on ok - I never touched the wires or plugs before the problem happened, and I've had two sets of eyes check em.
Good call there though... easy to miss.

 

[Tbars4]

...I really wish you had the original codes as we could definitely better help you then...

...It would also help with a little more background...Did you just purchase this vehicle or do you know the seller and the history???...Are you reselling the vehicle???

...You said you replaced the air filter...Was it stock???...Have you looked into cleaning the MAF???

...If you are having problems you will still get codes before the CEL comes back on after about 50 miles of driving...

 

[chance942]

What's the air filter look like?

I figured as much but thought I'd mention it.

8 plugs?? I thought Nissan determined that it wasn't very beneficial. Interesting

Anyway have you checked the injectors with say stethoscope or screw driver?

What was the vehicle originally brought in for? Problems or PM's?

 

[my98nnj]

The plugs were really fouled - seems like it's dumping way too much gas and running rich.

Check for a clogged cat.

 

[scrivyscriv]

We sent it out of the shop this afternoon and the front salesman was supposed to let the customer know it wasn't running right and we couldn't find out the problem... But he forgot to tell her, and it died on her after she left the shop.. After spending $1500 (no exaggeration!) on PM. Tbars it's a customer's truck and the air filter was stock. I'll pull the codes again tomorrow and see if anything else has come back up.

Chance, she didn't have any problems and told us it had never had problems before. We were doing an oil change and sold her everything else as PM since she hadn't had any of it done during the 62k miles she had on the truck.
2 plugs per cylinder does seem a little overkill, ha, and they're not easy to get to in the back to put wires back on. Haven't checked the injectors but probably will since it's back in the shop.

Plugged cat? I doubt it at 62k miles, but will check it even if only to eliminate a cause.

The thing that's throwing me is that the truck did not have problems, other than a rough idle from the O2 sensor, when it came in... So as the tech working on it, I must have done something to cause the fuel/ignition problem, and very much doubt the problem was a spontaneous unrelated event.

 

[Tbars4]

...This is a total shot in the dark...

...I don't think your code was a P0144 as I don't believe you have a third sensor...I would think that you had a code P0174 = System too Lean (Bank 2)...

..:scratch:...If that is the case, the fix could be very common and as easy as cleaning the MAF...Other things to look at would be found in post #2 of this thread...I hope it helps..
http://www.explorerforum.com/forums/showthread.php?t=252015

...If you have a good scanner, your guys should be able to pull up not only the current codes even without a CEL, they will be able to pick up the last couple dismissed codes also, unless someone unhooked the battery...

...I would like to add, the 02 sensor codes are rarely the 02's themselves but instead, a problem upstream...

...And here is a question, exactly what spark plugs (brand) did you put in...???

 

[scrivyscriv]

That code sounds close, if not correct. I remember it being a Bank x Sensor x readout. If I can pull up the original work order I'll see what codes I wrote.

As for a good scanner, well...
My shop won't invest in one. We have an old Snap-on that hasn't been updated in years, so I'm going off my little Mac code scanner... You know, the $90 one, quite unlike the $5,000 one I need here
And Mac was out of fuel pressure testers today so I can't check fuel rail PSI for a bad regulator.

I unplugged the MAF and the engine immediately idled down and missed like nobody's business - I won't rule it out but at this point replacing the MAF probably won't happen since we're going to eat the cost of troubleshooting and it's not obviously failing.

We pulled out Autolites and replaced them with Motorcraft platinum

Meh... I'm going to bed.

 

[Tbars4]

...Any update on this???..

 

[scrivyscriv]

Yep - our district manager visited the shop yesterday and authorized a purchase for a $4300 Snap-on scanner. Hopefully we'll find the issue pretty quick... and hopefully it won't have been my fault all along

 

[Tbars4]

..Just for a time reference, you are not going to work on the vehicle until after the new scanner comes in???...Do you have it at your work parked or does the owner have it back??

 

[scrivyscriv]

The shop did some more troubleshooting on my off day - ended up that the cat is plugged!

 

[Tbars4]

...This vehicle just came in for just some service and a cel???..My thinking then, this vehicle was causing a lot of problems before your shop got a hold of it...I am still really interested in what the original codes were on the service order...

 

[chance942]

Can I have the cat? It's just worthless,rusted metal anyway. You guys pay to ship it to me and I'll properly dispose of this for you.

 

[my98nnj]

The shop did some more troubleshooting on my off day - ended up that the cat is plugged!

And your welcome!

 

[scrivyscriv]

Yeah Tbars the customer told us she had never had any problems with the truck... It wasn't a daily driver and she was older so she may have just blown off any issues that the cat was causing.

Chance thanks for the offer! You're the man!

my98 if I haven't mentioned it yet, thank you, and you were right lol

 

[chance942]

Hey I try to make a buc...errrrr help out when I can!