Jump to content

Quick thoughts....


Trogdor636
 Share

Recommended Posts

So a friends mom has a 93 Pathfinder, she called me this morning and says it ran rough died at a stoplight when she came off the freeway. She was able to fire it back up, and seemed to run smoother when not idling, as she made it to a parking lot. I won't be able to look at it until I'm off work, so any ideas on things to check would be helpful. My first thought is MAF......

Link to comment
Share on other sites

Mine strangely did this due to the air filter being dirty, full of dust, etc. Ran way too rich when idling and would die. I'm glad it was an easy fix but definitely not what I expected!

 

Cleaning the MAF takes all of 10 mins too.

  • Like 1
Link to comment
Share on other sites

Probably not if it runs better at higher RPM.

 

Yeah, MAF wiring, coolant temp sensor, check the ignition components (cap, rotor, wires). Slight chance of a jumped timing belt so maybe check TDC for #1 to the rotor position while you have the cap off?

Got an Ohm meter on you? Need any test values looked up?

 

B

  • Like 1
Link to comment
Share on other sites

I can stop by my house and grab my multi meter. I have a Chilton/Haynes but I can't recall if it has values in it. Browsing the FSM on mobile sorta sucks but if necessary I can do it that way.

Im still a few hours away from being off work so any other ideas keep em coming! I'm hoping for simple MAF wiggle, but coolant temp makes sense as well. I did the timing belt about 6-8 months ago.

 

Edited by Trogdor636
Link to comment
Share on other sites

So are you ruling out the timing belt? :tongue:

 

That's about all I can think of that is something you can address in a parking lot somewhere. Timing, crank angle sensor, dizzy issues are possible too. I guessing fuel delivery is ok, but maybe a failing/failed injector. Make sure to check the ECU for stored codes.

 

Injectors should be 10-14 Ohms, I have had one that passed when cold and failed when hot, but you could tell by how it ran.

Coolant temp sensor should be 2.1-2.9 kOhms @ 68*, .68-.10 kOhms @122*, .3-.33 kOhms @ 176*.

 

Obviously looks for something disconnected and maybe bring a can of flammable to search for vacuum leaks? I prefer WD-40...

 

"Remove cam shaft position sensor, harness should stay connected. turn ignition on (do not start). rotate sensor shaft, does each injector make operating sounds?"

"Check canister purge and vacuum lines"

There are enough other things to check that I would tow or drive it somewhere where I could really work. :shrug:

 

B

  • Like 1
Link to comment
Share on other sites

Well, it fired right up and idled fine. No chance to pull any codes yet, but I followed her home (15 mile drive) and it was fine, even stopped for gas. The only unusual thing I heard was one of the injectors seemed loud. I can't say I've ever heard one click like this one sounded like.

Link to comment
Share on other sites

Most "injector cleaners" are more or less useless, and contain mostly kerosene. Fuel system cleaners such as Chevron Techron, Gumout Regane, and Redline SI-1 are much more effective since they contain PEA (polyether amine) which is a proven cleaner that doesn't leave deposits behind such as solvents would. And when a fuel system cleaner is in the gas tank, many shorter city trips (but not so short as to not reach operating temperature) are ideal since the time spent sitting between trips allows the cleaner to soak in and work better.

  • Like 1
Link to comment
Share on other sites

:aok:

 

I've used both Techron and Gumout Regane; since both contain PEA, they both work well as far as I can tell. Techron can usually be found as BOGO free at some auto parts store every month, but if not I usually just get Gumout Regane from WalMart since it can treat more gallons than Techron for the same or cheaper price.

  • Like 1
Link to comment
Share on other sites

check, clean and tighten the pins of the maf sensor harness plug with a small pick. most likely culprit. it's happened to me!

wideband was showing the mixture dipping as rich as 9:1 at idle. basically just drowning the engine in fuel. cleaned and tightened the pins and back to a perfect 14.5-15 afrs

Edited by Nefarious
Link to comment
Share on other sites

First thing I did was wiggle the MAF, because that was a problem on my 94 until I installed a new plug. Couldn't get it to die. Running fine as we speak, so fingers crossed.......

Link to comment
Share on other sites

check, clean and tighten the pins of the maf sensor harness plug with a small pick. most likely culprit. it's happened to me!

wideband was showing the mixture dipping as rich as 9:1 at idle. basically just drowning the engine in fuel. cleaned and tightened the pins and back to a perfect 14.5-15 afrs

 

Can you give more detail on how you go about tightening the pins of the MAF. I've cleaned mine a few times and know what it looks like but I'm just not understanding...sorry if this sounds like a stupid question.

Link to comment
Share on other sites

if you look inside the electrical connector you will see there are small metal tabs on the connector itself (female end) and pins on the sensor (male end). all you have to do is get a small fine pick and bend the two little tabs on the female end down towards the middle to kind of close the gap, which in turn tightens up the connection between the pins and the sockets. works really well to refurb old connectors. use a small amount of dielectric grease on it afterward as well to prevent further corrosion and make unplugging the connector easier in the future

  • Like 1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...