hello,

please take a look at my data and tell me if there is something wrong with it

data posted here http://forums.corvetteforum.com/c4-t...ting-data.html

thanks,
Dan

 

In your other post , you say that you changed injectors but 5 & 7 are still not working ... were you having problems before you changed injectors ? If so , it could be a head gasket or intake gasket .... might want to do a compression test and a vacuum check

 

yes the car had problems, the car was sitting for more than 7 years and had water in the fuel tank and in the fuel circuit and all injectors were rusted ...

I chaged with new one the fuel pump, fuel filter, all 8 injectors, TPS, IAC, knock sensor, water pump, new distributor kit, new spark plugs and wires, air filter, new coolant agent, cleaned the tb ...

checked for voltage with a multimeter on inj 5 and 7 and have 5V also have spark on spark plugs,

the only problem I see is or the two injector are stuck or bad timing or both

 

5 and 7 share the same intake runner gasket and next to each other so same section of the head gasket next to each other in the distributor cap. I would start on the outside and work your way in.

With the key on and engine not running all injetcor connectors shouldhave 12 volts on one of the terminals when measured to chassis ground.

Make sure there is no carbon or cracked cap between the terminals for 5 and 7. Make sure plug wires are not swapped with wire 5 on spark plug 7.

If you have a spare old injector that is known good plug it to the connectors for injector 5 and 7 and see if it clicks with engine running if yes then wiring is good.

Spray some carb clean on the runner gaskets and manifold gaskets to see if rpm changes. Remember the runner for 5 and 7 are next to cylinders 6 and 8.

Pull the plugs for 1 3 5 7 and see if they all look the same if not put 1 and 3 in cyliders 5 and 7 and see if the skip moves to 1 and 3. if 5 and 7 have oil on them suspect bad manifold gasket.

Do a compression test while the plugs are out and compare 1 and 3 with 5 and 7 if lower suspect a head gasket or rocker arms and pushrod problem.

Check coolant for combustion by products kits to do this are available from most parts stores in the USA and not doubt in Europe somewhere. This would definately mean a bad head gasket or cracked head.

If all else fails you just have no choice other than totake off the intake and cylider head and find out what is wrong.

I know this is all very simple sounding but at least an orderly way to trouble shoot the problem. The most important thing to ask is why was the car parked so long that the inectors rusted and gasilne turned to varnish. Did it have the same problem then and could not be solved and the owner just gave up and abandonded the car to the corner of the garage. If that is the case then all the work so far has only put the car back to where it was when parked.. broken with the original problem.

I hope this helps you solve your problem.

 

It is showing DTC 43 ; electronic spark control module and ECM is pulling 6 degrees of timing out all the time( red line in graph ) from knock retard at warm idle

 

Something strange with the MAF signal. It is fixed at 16.2 gm/sec which is very high for a 700 rpm idle.

7-8 gm/sec would be expected with some variation in the signal for warm idle at 700 rpm.

Has the max airflow vs rpm table been adjusted to explain this 16.2 gm/sec? If not I'd say its a malfunctioning MAF.

With this airflow reading, it should be running very rich, which is also indicated by the injector bpw. It must be very rich if running as shown.

A normal idle with 23# injectors should be approx. 1.5-1.6 ms.

Disconnecting the MAF for a test should bring the AFGS down to a reasonable range for it to idle.

The default airflow should be approx 8.32 gm/sec (4 + (0.08 * 54)) with the current IAC position. This should be close enough to actual to idle reasonably well.

 

Disregard my last post regarding MAF signal. Just checked your profile. You have a 91 ($8D). I was using the wrong version of datamaster to display.

Now using 8D.

It should still be running very rich as shown by the bpw.

 

Check the connection to your sensor. I forgot to plug one of mine in and had the same problem (DTC 43, constant knock retard). It ran pretty rough too.

If it is connected, unplug and check to see that you have +5V at the connector to check the wiring to the sensor.