1995 J-30 Is it going to come back?

[johnofbham]

That's it! I've done all of the stuff within reason to make my J-30 run but it won't. Throttle body and MAF cleaned well, Seafoam, plugs, fuel filter and EGR lines cleaned of carbon deposits on either side. Will not run at low idle. Must be at 3000rpms to continue running and on highway will not go faster than 65 or 70 with accelerator on floor. Fuel pump whines and mechanic swears it's an air problem. Not sending codes either. Have reached a new level of frustration after three years of good service.

[johnofbham]

What say you.
Vacuum leak, IAC, EGR, injectors or ECU.
I really need help.

[yodawill2000]

No codes makes it tough.
Fuel pump whining may be the only clue to go on.
Does the mechanic have the ability to test fuel pressure ???
If the J is anything like the Q it has three modes.
Idle, Cruise. and Wide open.
Someone here should chime in on what the fuel pressure should be.
A failing pump would DANG sure cause those symptoms.
Come on Guru's .. Help us nail this issue !!!

[johnofbham]

thanks yoda. It sure is backfiring often at it last breath and is beginning to run for shorter periods, perhaps 10-15 seconds before cutting out.

[johnofbham]

I saw the specs on another site for fuel pressure and I'm going thru history but it's a long process. Could it be the fuel pump, possibly even leaky line? Didn't really smell fuel before I started cleaning everything.

[driverdriver]

I've asked one of the techs to step into this thread with thoughts.

[johnofbham]

Many thx driverdriver. I hope it is fuel related because I can grasp that. The rest is a freakin' treasure hunt.

[ProudNissanFreak]

See, I had a fuel pump issue on my B14 which would cause it to not run at low idles, but it didn't have an issue with going past 70mph. From my experience, your idle issues may be fuel pump related, but I'm not too sure about the speed.

[johnofbham]

See, I had a fuel pump issue on my B14 which would cause it to not run at low idles, but it didn't have an issue with going past 70mph. From my experience, your idle issues may be fuel pump related, but I'm not too sure about the speed.

Well I might have a dual problem with fuel and not shifting at higher speeds.

[GerryO]

These links list many items that can be cleaned and checked using a multimeter. Look for something simple.

http://home.swipnet.se/e-solutions/IdleTech.html

http://home.swipnet.se/e-solutions/IdleTech2.html

http://home.swipnet.se/e-solutions/Contactclean.html

http://home.swipnet.se/e-solutions/Vacuumleak.html

[johnofbham]

No codes makes it tough.
Fuel pump whining may be the only clue to go on.
Does the mechanic have the ability to test fuel pressure ???
If the J is anything like the Q it has three modes.
Idle, Cruise. and Wide open.
Someone here should chime in on what the fuel pressure should be.
A failing pump would DANG sure cause those symptoms.
Come on Guru's .. Help us nail this issue !!!

Can fuel pressure, regulator, pump problems be akin to trans not shifting at higher speed (ie70mph) ? This seems a latent symptom as well.

[GerryO]

Can fuel pressure, regulator, pump problems be akin to trans not shifting at higher speed (ie70mph) ? This seems a latent symptom as well.

By not shifting at higher speed do you mean no OD lock-up (engine rpms at 70 mph should be in the 2,800 - 3,000 range) or no down-shifting with more pressure on the gas pedal, or both?

What's the TPS output voltage?

[johnofbham]

Can fuel pressure, regulator, pump problems be akin to trans not shifting at higher speed (ie70mph) ? This seems a latent symptom as well.

By not shifting at higher speed do you mean no OD lock-up (engine rpms at 70 mph should be in the 2,800 - 3,000 range) or no down-shifting with more pressure on the gas pedal, or both?

What's the TPS output voltage?

No shifting and certainly no cruise with variations of rpm readings. Can red line it but no speed and of course very sluggish beneath 30 mph and must force it above that to keep it going. No means to measure TPS voltage output and both - no OD or downshifting.

[OutToWinPAHC]

Reminds me of maf issues, or a simple vacuum leak. I too and inclined to think a vacuum leak.

[johnofbham]

Reminds me of maf issues, or a simple vacuum leak. I too and inclined to think a vacuum leak.

Well the diagnoses says it's the maf according to mechanic who was able to retrieve the code. Not completely sold but yes he thinks that's the culprit too after fuel pres. readings and testing wir. har. etc.
Ebay Motors $79 Wholesale used $112 Retail $200+

Thanks everyone for your help. Greatly appreciated.

***Note: Pull a Part had two like models but no mafs.
Anyone know what will crossover to suffice and would you take a chance on a maf with over 100k on it for a car you hope to get at least 75k more out of?

[yodawill2000]

There is a few guys parting out J's here.
I have bought several things from Swimshark and they have all been in PERFECT working order.
I recall a guy with a 97 also parting his out as well.