Help with z24i

[presharrison]

Hey guys,

 

I have an 89 d21 with the z24i. For about a year now I've had a rattle on startup which disappeared once the engine built some oil pressure/light comes off. I always assumed it was the timing chain. Probably shouldn't have deferred it but it only made noise right at startup, moreso with cold weather.

 

Now it will only run on 2/3 cylinders. Straight fuel dumping in the crankcase. Verified spark on all 4 exhaust plugs (just because they're easier to reach.) Had a spare dizzy around so just slapped that on hoping it was the optical sensor. I realize now I need to get a timing light and fix the ignition timing but I have it as good as I can get it by ear. 

 

Thought maybe I jumped time. Pulled the valve cover. The timing chain looks brand new, no slack at all. Is it possible it moved still?

 

I also pulled the fuel pump relay thinking maybe the 1 injector was stuck open? Tried to bottle feed it. Just resulted in catching the throttle body on fire (lol.) 

 

Any advice would be greatly appreciated. I know I should double check the order of the plug wires but it ran fine and I haven't touched them other than to put the inline spark tester in.

[datzenmike]

I have never heard of an L or Z series timing chain jumping. There's just not enough slack for that.

 

Fuel in the oil will thin it. Find out if fuel is getting into the oil. Take the air filter off and watch the two injectors. Is there gas dripping? Check the engine diagnostics for a thrown code that might point to the problem. If the temperature sensor (not the temperature sender for the temperature gauge) is not working then the engine management will think that the engine is never warmed up and will run it rich. Check for an O² failure code. EFI never goes into closed loop mode.

 

Check for spark on the intake side by pulling one wire off, stick an old plug in the end and hold against anything grounded to the engine.

 

 Check the obvious like your valve lash. Tight lash can cause a cylinder to drop. Clearance is 0.012" on all.

 

Check ignition timing I think 5⁰ BTDC

 

Plugs MUST be NGK BPR6ES intake side and BPR5ES on the exhaust

[presharrison]

Hey Mike thanks for the help. I got a 12 (Airflow meter) and 23 (Idle)

 

Idle has always been too high anyways. Is it possible the code 12 can make it run that bad? It's definitely going into the crankcase, the dipstick smells like gas and I'm getting black smoke out the exhaust. Unplugging the MAF seems to lessen/stop the smoke but it still is barely running and not firing all cylinders.  

 

I'm thinking I'll replace the intake bank of plugs, pull the distributor again and verify it's timed right with the oil pump, time it 5 degrees BTDC like you said. I saw the valve adjustment should be done warm, is there a base adjustment I can do while it's cold? I hate running it like this so I don't exactly want to warm it up first. 

[datzenmike]

If there is a failure in the system it goes into a 'limp home' mode. Because there is an O² sensor the mixture could go dangerously lean so an over rich is selected. It's assumed the owner will notice the very poor mileage and find out why.

 

 

Engine must be fully warmed up for the following tests...

 

Air Flow Meter

The test for the air flow meter is remove air filter, pull back the rubber boot exposing the 4 connections, turn ignition ON, measure voltage on the B wire. Should be battery voltage. If OK...

Disconnect connector, measure resistance from C terminal to ground. Should measure 0 ohms.

 

The test for the ECU/AFM is to remove passenger seat, connect AFM plug, start engine, measure voltage between terminal 31 and ground. Rev engine, volts should vary between 0 and 5 volts. A failure here requires the AFM plug be disconnected and the ECU 16 pin connector be un plugged. Measure the resistance between the D harness wire and the ECU #31 wire. Should be 0 ohms. Inspect each end of harness for damage to the pin connections. Sometimes just unplugging and plugging back in improves the connection.

 

Erase stored codes, take for a ride, perform the self diagnosis to confirm the problem is gone.

 

Idle or throttle Position Switch

.Find the check connector under dash near the hood release lever. Turn engine off, measure resistance between pins 9 and 15. Should be 0 ohms and infinite resistance when gas pedal depressed.

Check ground... disconnect 20 pin connector at ECU, disconnect idle switch connector, measure resistance between #18 on ecu harness plug and terminal C on idle harness. Should read 0 ohms.

 

  Erase stored codes, take for a ride, perform the self diagnosis to confirm the problem is gone.