1990 Toyota 4Runner Tune up blues

AHONDANUT

MEMBER
1990 TOYOTA 4RUNNER
6 CYL
2WD
AUTOMATIC
177,000 MILES

Hello,
I have a new automotive nightmare I desperately need some assistance with. I just bought a 1990 4-runner 2wheel dr 3.0 3VZE as a project vehicle/work truck. The truck was running a little rough but not that bad and decided she needed some tune up attention. I replaced the plugs, wires, distributer cap & rotor. Now the motor has no power under load! It Idles good but goes from 0 to 60 in about 5 miles sputtering all the way. It gets worse as it warms up or if the gas pedal is requesting more. I've checked the timing all the vacume/intake hoses that I can find and all seems to be in order. I am beside myself! The funny thing is that I was removing all the old components and wondering how the truck was even running at all, & now with all new stuff it's running worse than ever? I did notice that the NGK-G power plugs that I used were gapped about 4 thousandths (.035)over the gap of.031 that my repair manual calls for. I did not think it would hurt with a small increase of the gap so I left it be, was I wrong? :-(
PLEASE HELP :-)

4 Replies

MHPAUTOS

MECHANIC
31,937 POSTS

Hi there,

The plug gaps will be fine, I would start with a scan to check for any unresolved fault codes, you don't always get a check light with all codes, start here.

Mark (mhpautos)

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Wednesday, February 3rd, 2010 AT 6:55 PM

AHONDANUT

MEMBER
13 POSTS

Mark,
Thank You, Do you know if this vehicle has an
OBD-1 or 2 set up? And if so can you tell me where the test port is loceted and posibly have a code chart. Unfortunately my Haynes manual has nothing on the diagnostic code scenario, what a bummer!

Thanks in Advance
PEACE <><

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Wednesday, February 3rd, 2010 AT 7:27 PM

MHPAUTOS

MECHANIC
31,937 POSTS

Mitchell 1 says the diagnostic connector is behind relay box No 2, but it has no pic to show you, our version in Aus is a bit different, but i think you should find it in the engine bay, either L/H side rear or R/H side rear, it is a small black box with a lid, bridge out terminals as shown in pic, read code as flash codes on check light, I.E 2 long flashes and 4 short flashes is code 24.

https://www.2carpros.com/kpages/diagnostic_trouble_codes.htm

Mark

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Wednesday, February 3rd, 2010 AT 11:27 PM

AHONDANUT

MEMBER
13 POSTS

Hi Out There,
I have just realized how long it took to get back to ya'll, it's been a hell of a ride and still not done yet.
OK here we go. I pulled the codes off OBD-2 got a 51 & 52. I replaced the throttle position sensor and inspected wiring thoroughly, code 51 went away, after some lengthy research on the Knock Sensor and wiring problems on the 3VZE I discovered a completely burned to a crisp (in two) shielded knock sensor wire. Pulled al the stuff off needed (thanks Toyota for the wonderfull idea to place the KS under the intake and the run a tiny shielded wire between the driverside head & intake-BRILLIANT! Anyway to make a short story long I checked the KS and was good replaced the wire & have eliminated the 52 code. The motor has much improved performance compared to what it was but still seems excessivly sputtery under load and still a significant loss of power on the road. I literally still go 0-50mph in 5 miles and it struggles to maintain that blistering speed. As far as I can tell the ingnition timing is correct. When I put a timing light on it the mark is right where it supposed to be at idle and I notice it advances as the rpms increase as it should which brings the point again that at idle motor sounds beautiful. At this point I'm very confused because I have no check engine light and there are no codes? What I should I consider as my next move.

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Thursday, March 25th, 2010 AT 9:18 PM