BangNgearz

Not sure if it has been covered, just haven't had the time to search. Will a failing dizzy cause the timing to get thrown off and create a bad miss and bad fuel economy? Just about everything else has been replaced and tested. Some insight would be appreciated .

75w90mantraN

I think so. Which part you referring to? Cap and rotor, or electronics like igniter module? Give more background and a better answer is a stone throw away.

BangNgearz

Well, I have replaced the module( it failed earlier this year), put new cap and rotor on same time. Put new plug wires on after pulling one apart when changing plugs. I had changed the tps out and then put the original back in. Messed with the afm but put it back to stock. Also put a "cold air intake"lol and put on a set of headers and gutted cat.

BangNgearz

I also can jump the diagnostic port and bring up a code 12 which is a momentary rpm signal loss. No other codes. Forgot to mention that I did a head gasket job and tbelt and those goodies on the front of the engine. Double checked all the timing marks before reassembling. Did a egr and pair valve deletion as well. New denso 02 when exhaust was done. Still have stock muffler tho.

75w90mantraN

Cool.

Be good to check compression after that HG job.

I dont know...maybe check for vac leaks. A lot was taken apart.

Rotor lined up with your timing marks?

May not be the distro.

I had to triple check my HG job on another engine. Missed a few things.

BangNgearz

Yep, checked everything that was removed, all marks lining up, tried carb cleaner and map gas to check for vac leaks. I get really good spark on all cylinders. The last time I put a timing light on it the mark was advanced way far out. Really weird, but it ran like it was supposed to. I also have to keep adjusting the idle screw on the throttle body every so often to keep the idle around 800-900. It goes really low or jumps up to about 1200-1300.

75w90mantraN

Was the problem present or before all the work?

I might guess, could be wiring related...

https://www.google.com/amp/s/www.troublecodes.net/toyota/toyota-92-95-pickup-or-4runner-3-0l-or-93-94-t100-3-0l/%3famp

BangNgearz

Sadly it wasn't doing this until after the head gasket job. I was getting close to 17mpg before that. All the wiring is put to where it was before. The egr and pair delete was done after I had it running following the hg job. It was running the same way before and after. There is that coolant sensor on the back of the motor that hasn't been replaced tho. Not sure about it being a part in the problem.

75w90mantraN

So with the tps and afm being touched, what did you mean by messing with afm? Why put the original tps back in? Just trying make sense of the situation.

Timing light shows marks are advanced...against what specs?

Gutted cat...meaning no more?

Compression numbers if possible...

So basically engine hesitation at idle or acceler or both? Any other symptoms aside from what you mentioned? Are you able to hook up a scan tool with OBD 1 capability?

Coolant temp sensor is likely related in some way. The PCM/ECM takes that input, along with others to influence performance like fuel trims. Be good to try and trace that to where it needs to be connected.

I'm thinking timing, air, and/or fuel. You've ruled out spark it seems. Assuming its been spark tested.

Hopefully sound advice comes your way.

BangNgearz

I adjusted the afm leaner to see if would help with the running rich but no luck. So I put it back to stock setting. The new tps was taken out cause it ran weird when I grab the connector and wiggled it. Original one didn't change when I did that. Timing light mark on crank was so far advanced it didn't get to 10° until I turned the distributor clockwise till the adjustment had no more. It ran real bad like that. It doesnt have much hesitation, more of a miss fire. It misses and has lack of power throughout the power band. Its a real turd on the highway in 5th, having to downshift often. Going uphill is a real battle. The cat is there but just the shell. Haven't got around to the compression test. The guy that did the head work for me had to do reseat all the valves and skim the the mating surfaces. With the way it runs and smells so rich, everything points to the ignition timing .

jbtvt

Distributors are easy to check. Sounds like your timing belt or distributor is off a tooth though. I have a couple good dist for a 3vz I'd let go pretty cheap but doubt you need one.

BangNgearz

I double checked the belt and spun it over three times before I put it back together. I even took off the front cover just two weeks ago to check the cams. The next thing I guess I should is to check the crank gear to see if the marks line up with the cams. Doesn't the distributor determine the cam position and send that info to the ecm?

jbtvt

Newer engines have Cam and crank pickups but not the 3vz. Very easy to have the helical gears on the distributor off a tooth, done it myself. If everything isn't lined up perfectly your ECU has no way of knowing where anything is positioned and it will throw your timing is off, like it is now. There are other threads on here detailing the distributor alignment issue. Def check the crank position too, if that's not on its mark when the cams are on theirs, there's your issue.

BangNgearz

Come to think of it, the crank gear is lined up because when I last checked the cam gears I had the crank pulley mark at 0° on the timing tab with cam gears at their marks. Im sure that the dist is in correctly because I lined all marks and had the rotor pointing in the no 1 cyl direction. And the dist is in the middle of the adjustment slot. What about the pickup coils in the dist? Could they have a part in this?

75w90mantraN

If its the pickup coils, you shouldnt have good spark reaching the plugs. You mentioned you got good spark.

Not all is what they seem. Check and recheck. The problem presented after the work.

With the misfiring throughout the rpms, and recent top end work, I wonder about the valves. Take it back to the place and see if they make good on their work.

Other rabbit holes worth checking are fuel-related components like leaky injectors.

BangNgearz

I know the guy personally, he's done racing motors for me and he talked me through all he did to these heads.

I've also changed out the injectors which made an improvement over the stock ones.

One thing that comes to mind is that sometimes it has a hard time starting like the timing is too far advanced.

Every once in awhile it actually runs smooth but still lacks power.

75w90mantraN

Hard start issues...like not cranking, or crank-no start?

I would check fuel pressures at idle and open throttle...along with whether it can hold pressure after shut off.

Everyone makes mistakes still, no matter the years of experience. Does he guarantee his work at least? Just some verification.

Wonder what this turns out to be.

BangNgearz

When starting, its cranking normally then it trys to start then loses its catch, like the timing is out 180°

75w90mantraN

Loose bolts on any of the timing gears, dizzy?

Missing teeth on the sprockets or belt?

Could it be possible that the distributor shaft is off when it was placed back on the cam?

BangNgearz

If the distributor was installed one tooth off wouldn't it have trouble running at all?