'79 Fuel Injection Poor Performance Over 60mph

[timvw7476]

Well at this point, waiting for The Visit, I would suspect nests/rags blocking
the blower fan ducts. The rear tin pieces have to come off to pull the fan
and investigate.

[vwwestyman]

Perhaps it is turning off because it gets so hot the Temp 2 sensor cuts it off?
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Dave Cook

President, Wild Westerner Club

1978 Champagne Edition Westy, repowered to '97 Jetta TDI
1973 Wild Westerner
My Thing

[Wildthings]

You can inspect the top of the heads for mouse nests by looking down through the holes in the tin for the spark plug wires. With a mirror and some contortion you can even see the top of the oil cooler, a boroscope would make this easier and more effective.

You could even just take one of the claw style picker-uppers and fish around under the tin to see what you can grab.

[RidinRetro1973]

I don't suspect rags or mice nests. The overheating problem only arose since this new mechanic had swapped his parts onto my engine. And he's only had it since March.

Could the fuel pressure regulator or the fuel pump get too hot/fail and cause low fuel pressure causing #3 to not get enough fuel?
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[busdaddy]

Mice are industrious little critters, with a source of nesting material nearby (like VW seat padding or the underhood isulation from another car) they can construct a cozy little love nest in an 8 hour shift, and they can squeeze between the fan blades too.

Yes it sounds like a F'up on the last mechanics part, but have a fish through the plug holes as WT's suggests anyways.
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[timvw7476]

The last time your bus ran hot while you were there, was there any engine
pinging when pulling away from stops?
If the air shutter on the oil cooler side is loose, it tends to block air flow
to the cooler, seats on the other side of the engine, cylinder 1 intake in
particular, like to fall out at that point. The bore scope is sounding like the
best idea to see the flap action. Or whatever secrets this engine is hiding.

[Hoody]

If this mechanic is throwing his arms up that fast. He either doesn't want to deal with it or is incompetent. There are very simple tests to check the internal integrity of the engine. It sounds to me that he doesn't have a clue what to look for in terms of L-jet. I still think your wiring harness is fried....and it doesn't take much for a toasted 37 year old wiring harness to heat up, become completely useless and shut down your L-jet really fast. I would invest in a new wiring harness from Kyle and contact Colin as to what else you may need for his visit. Good luck!

[RidinRetro1973]

Well the Westy came back home today,

It runs, just not very well. The performance is terrible, very sluggish and loud. Sounds to me like a lot of valve noise or something that it didn't have before, kind of a low rumble and chatter when under load. Goes away at higher rpm. Check out the video below. The mechanic swapped out my drivers side intake and plenum because my runners didn't line up correctly. Other than that, he just put all my original parts back in.

He had swapped in his "tester" ECU, AFM, distributor, and injectors before we went on our test drive that resulted in the break down. I'm still suspicious that these may have been the cause.

My original ECU was swapped last year by the previous mechanic. I never saw the ECU he put in, but he left my original in the Bus. After getting the Bus back today, I noticed that the ECU in the back of the Bus was the replacement, and my original was plugged in. I checked the part number on the replacement and its for a Cali '79.

My original ECU:

Cali replacement:

From what I've read here, the Cali ECU's don't play well with federal AFM's or harnesses. So earlier this year when I was adjusting my AFM, it was with the cali ECU, which would cause issues, right?

Cali on the left, federal on the right:

I spent the day going over what the mechanic did. He thought the thermostat cable had broken, luckily it wasn't. Somehow the cable came unthreaded from the thermostat. I hooked it back up properly.

I noticed the drivers side flexible heater dump hose had come loose from the metal dump tube and was dumping the engine heat onto the fuel pump... It wasn't like this when I dropped it off at the shop. I bought a new hose and hooked it up.

While underneath, I noted that the fuel pump is a reman from fuel injection corp. During my testing over the winter, I never managed to test fuel pressure. I want to make sure the FPR is working properly and the pump.

What do you guys think my plan of action until the visit should be? The Bus idles great, but it lacks power, seemingly worse than when I dropped it off at the shop. The problem seems like it still lives in cylinder 3. The runner on 3 doesn't get as hot as the other 3, and thats where the noise sounds like its coming from I want to do another compression test, check the valves, check for mice nests, do an oil change, go through the harness again, and adjust the AFM. I'll get in contact with Colin before the visit. On Hoody's recommendation, I sent an email to Kyle about a new harness last week but haven't heard back.

How's it sound to you guys?

Link


Link

Thanks again for all the help.
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[Wildthings]

If you are only running your engine for short periods of time the valves are apt to leak down each time it sits for more than just a few minutes. Just the way it is. If this bothers you you could back the adjustment off the give a hair of lash to the valves say .004-.006" as this will cause the valves to pump up faster when cold. You will need to get back and preload them once you figure out your problem and put your rig into normal service.

I would not think that an ECU that was designed to work with an O2 sensor would play well with a system without the sensor, or vise versa.

[cmonSTART]

Link


In this video, what is that deep knocking sound when the engine is revved? I know sound quality can be funny on cell phones, but I hear what sounds like some valve clatter, and then this deeper sound.
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de K1IGS

[Abscate]

Love the Bay and the EVay! Great combo!
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[Randy in Maine]

Are you 100% sure that the wiring harness is hooked up to the correct members? Using the factory hook ups....Blue is cold start valve, black is the AAR and brown is the TTS.

After that I would do a volume test of the fuel pump to make sure you are getting what you need. 1L in 30 seconds IIRC. Make sure that 10mm hose between the fuel filter and the pump is good inside and not kinking internally.

Then I would start sealing off the various vacuum leak prone sites to see if that identifies a leak. Duct tape and golf ts are your weapons.

Is the seal between the throttle body and the air plenum 100%? Tightened down evenly?

Distributor advancing smoothly without vacuum and then with?

Is the ERG valve completely sealed off and not allowing a vacuum leak?

Start with the power brake booster at the air plenum. Carefully inspect the S boot and everything that plugs into it. Do not forget the EEC valve in the air cleaner. A hand vacuum pump is handy to own.

[RidinRetro1973]

To clear things up a little, my Bus has been converted from hydro to solid lifters.

I double checked and adjusted the valves today to .006. They still chatter quite a bit.

I pulled the plugs because the mechanic took out the plugs I recently put in. He put in Bosch WR8CC's. While I had the plugs out, I used a dentist's mirror to peep down the holes to the tops of the cylinders. No mice or nests to report.

How do these look? Cyl 4 on the left, Cyl 3 on the right.

I checked the timing at idle and it was around 20* BTDC. I didn't check what he had set it at 3500. I reset the timing myself to 28* BTDC at 3500 with the hose disconnected. My idle timing still falls to 12 or 14* with everything hooked back up. Should be 7.5* at idle right?

I took it down the road for less than a mile. Makes a lot of noise but not a lot of power. Flooring it lugs the Bus down hard and it still has the low grumble at low RPM. Sounds like its coming from the drivers side of the engine. When I got back, I unscrewed the oil fill cap and undid the S-boot from the AFM and smoke came out. Its only 80* here in Chicago. The bumper, and top of the shroud are really hot.

I threw my spare AFM in and there was no change in performance. Getting on the throttle blows black smoke. If i shut the ignition off, it has a really hard time restarting.

cmonSTART asked about the sounds in the video, yes the low grumble is what you hear.

Randy in Maine I double checked to make sure the harness is hooked up properly, it is. Over the winter I suspected a problem with the booster, I plugged the hose coming from the plenum and it didn't make a difference. Everything on the S boot is tight, and there aren't any cracks in the s-boot. The distributor advances smoothly throughout. I'll check the throttle body and vacuum leaks. The EGR is blocked off and sealed up.

(starts reading about subaru swaps)
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[cmonSTART]

I don't like that sound. I would love to see an oil pressure gauge on it with the engine warmed up.
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'78 Bus 2.0FI
de K1IGS

[skills@eurocarsplus]

[RidinRetro1973]

So I started reading about sunk valves and dropped seats...

I found a thread about checking the valves with a straight edge. I checked 3&4 over the winter based on someone here's recommendation and they checked out fine. Today I checked them again with the same result. Completely straight across each valve spring.

I checked 1 & 2 for the first time and the #2 intake, second from the rear is noticeably lower than the other 3. This would indicate a dropped seat, right?

Based on my compression tests from the winter, #2 had the lowest compression of the 4 at 120...

Its a little hard to tell from the photos, but the second from the left valve doesn't touch the straight edge.
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[cmonSTART]

[RidinRetro1973]

[Wildthings]

Does your #3 plug smell of fuel?
What about your exhaust?

Put a new plug in the #3 hole and see if that makes any difference.

Pull the #3 and #4 injectors and check the spray pattern.

[RidinRetro1973]