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B21 Kjet low idle, no power, '78 242

2turbotoys

2turbotoys

Salaminizer
Joined
Nov 13, 2007
Location
Reading pa
I've been trying to diagnose a low idle/no horsepower issue in my "new" 1978 242. When the car got here, I spent a day going over various things, installed a new battery and fuel pump relay, and it seemed ready to go. Fire it up and the idle is about 450-500 RPM. It's a solid idle with no misfires. I take it for a drive, and it seems gutless, very slow. This was confirmed when coming home. I live on a very steep hill, and I wasn't sure the car would make it up. 2nd gear, about 25 MPH, at 3K RPMS and won't rev any further.

I thought maybe a clogged cat, and it was suggested the timing gears were off. I checked timing first, TDC on compression stroke, piston closest to the front bumper, and all the gears are in the correct position.

I removed the cat, which required saws because it's a welded in aftermarket unit, and unfortunately it didn't look bad inside. The flex pipe I got as a temporary fix doesn't fit that well so I now have an exhaust leak. The results of removing the cat were it now idles at 600 RPM, and it backfires/pops on deceleration in the exhaust manifold every single time. I would think ignition timing or very rich for that little gem...Still no horsepower.

No obvious vacuum leaks or unhooked lines. Oil doesn't smell like fuel.

After some searches tonight it seems the next steps to do tomorrow are:
Check injector seals
Getting a full ignition tuneup tomorrow
Check ignition timing
Clean metering plate and idle air motor thing

What do you guys think? What is the next step?
Thanks!
 
I forget, but does this car have Lambda-Sond? If it does, attach your dwell meter to the red wire near the battery that's hanging loose with a black plug on it. Make sure that the dwell meter is reading somewhere between 51 and 59 degrees dwell. If it isn't, check the relay next to the headlamp relay and the junction block on the driver's inner fender. Make sure it's not corroded to heck. If your other 242 is also Lambda-Sond equipped, you could also swap the relays between the two and see if the problem moves to the '79.

-J
 
I appreciate the link! I actually have the paper greenbooks, and looking thru them for serious stuff is hard. Section 2 Group 23 is repeated in that list at least 4 times. I did go through all the manuals withe a "ci" search, I already all the manuals relating to CIS and they really aren't helpful.

Manual Section 2 Group 24 is CI fuel injection system, Fault tracing. Example: "symptom low top speed (closest description to my problem) In order of recommendations: Check ignition timing (on my list of stuff to do), Check engine compression (I know thats fine), then it says Throttle valve, B21 refer to op. D2. What does that mean? The manual has nothing labeled D2.

Section 2 Group 23 manual, I found a D2 and D3 relating to the CO2 output and adjusting the mix. "Connect test equipment." No mention of what that equipment may consist of, and has nothing to do with a throttle valve. My greenbook collection is not complete, but I do have 80 or so of them.

Hoping someone has some ideas I can do at my house without unspecified "test equipment". I do have most of what is needed to junk Kjet and do EFI on Megasquirt but I really don't want to if I don't have to.
 
It does have Lambda Sond. Thanks, I will try that. My '79 is running EFI on Megasquirt that the PO installed so I may not have interchangable stuff anymore, but I will check. Thanks!
 
What is that relay for? I just went out to unplug it and check it out, but the harness is a bit stuck so I'll check it out tomorrow. My '79 does not have it or the harness anymore, just checked.
 
Good call, I checked though. Airbox is clean with a reasonably clean K&N filter in it. I tried to look for any intake/exhaust restrictions. I did not pull the intake piping however, but I will tomorrow to clean the metering plate and throttle body. And will shine a flashlight through it to check for holes.
 
Throttle valve is the throttle body.

Test equipment would be a dwell meter or, in the case of a non-Lambda car, an exhaust sniffer.
 
The pics show an exhaust sniffer, which no one actually has at home. I understand what the throttle valve is. Do you know what that relay is for? Since I can't easily unplug it, it is probably corroded, the part number certainly is haha. I have to look to see if my multimeter has a dwell meter function, I do not have a dedicated dwell meter.
 
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The relay supplies power to the ECU and the frequency valve. The O2 sensor is connected to the ECU.

Do you hear a buzzing noise when the engine is running?
 
I don't hear a buzzing noise, but the exhaust is pretty loud even before I caused a leak...so its hard to say. I will listen for one and report back.
 
The frequency valve is pretty loud. You'd definitely hear it with the engine running and the hood open.
 
Touch the valve to verify that it is operating. I can't hear mine but that probably is my hearing.
 
The relay in question also provides power to the control pressure regulator which will give you a very rich mixture and poor performance if it never gets heated. I've also had fuel pump relays with a fail on the 87b output which feeds that lambda relay.

Another lambda kjet problem I've had was the power wire in the lambda computer had backed out of the spot on the connector. Had to bend the tab on the contact terminal so it latched in again.

How do the spark plugs look?

Have you checked fuel system pressures? You'll want to do that with kjet.
 
So here's what happened so far today:

Relay looks great, popped the cover off and everything is shiny, contacts are clean.

Started the car, no buzzing or vibration from the frequency valve, which I assume to be the thing that looks sort of similar to a fuel injector. I let the car warm up fully while listening and touching the valve, it never made a peep. Guess this is a bad thing.

There are visible magic marker lines on the distributor that show it has been turned clockwise at least a 1/4"

dl242gt- the plugs are awful, 4 tip platinum and visibly work. Putting in good old NGK copper plugs when it cools down.
I will try to figure out where the lambda computer is and look at the connections.
I looked up how to check the fuel pressure and have no idea where to get that crazy looking test rig. http://cleanflametrap.com/kjetGauge.htm this is NLA. Seems like a real pain in the butt looking at that and other sites...
 
2turbotoys said:
....
Manual Section 2 Group 24 is CI fuel injection system, Fault tracing. Example: "symptom low top speed (closest description to my problem) In order of recommendations: Check ignition timing (on my list of stuff to do), ...
Click to expand...

After reading your thread, I would suggest you start on page 6 if you don't have a dwell meter. Make those voltage checks while the frequency valve is still not buzzing, and list the results here so we can look over your shoulder. Sounds to me like something is completely missing. :)
 
TurboBricks brand K-jet pressure test equipment

I see that checking the ignition timing is on the 'to-do' list but have you done that. My barn find distributor was installed one tooth off with an attempt to adjust it from there. A little confusing.

Try here for more than you want to know about K-jet operation.

http://forums.turbobricks.com/showthread.php?t=289775

Check voltage at O2 sensor. Should swing between 0.4v and 0.8v. These old sensors are only good for 25k miles
 
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