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802 xl engine problem

1rv@gmx

New member
I have a 1999 402 Silverton with crusaders 802 xl engines. My port engine will not go much past 2000 rpm it then falls like the switch has been turned off then if I back the throttle off it resumes running. The buzzer on the dash goes off at the same time but stops once I back off.
How do I troubleshoot this and find if it’s electrical or fuel related ?
 
Crusader didn't make a "802XL" engine....is it the 502CID? if so, is it the carb version or the TBI one? A serial number helps because they made a lot of changes in the late 1990's...

If its the injected version, probably fastest to scan the ECU with a scan tool...
 
Crusader didn't make a "802XL" engine....is it the 502CID? if so, is it the carb version or the TBI one? A serial number helps because they made a lot of changes in the late 1990's...

If its the injected version, probably fastest to scan the ECU with a scan tool...
That was a typo it is a 502 xli it has a carb with 2 injectors. Like the old TBI Chevy had. I have good gas, plugs and wires, all my filter are new this year. I just don’t know where to start troubleshooting?
 
Crusader didn't make a "802XL" engine....is it the 502CID? if so, is it the carb version or the TBI one? A serial number helps because they made a lot of changes in the late 1990's...

If its the injected version, probably fastest to scan the ECU with a scan tool...
Thanks for the reply and is it possible to scan for errors on this system?
 
Your engine doesn't have a 'carb', it is the old GM TBI unit...

Yes, you can have the ECU scanned or you can bite the bullet and buy the s/w and adapter or a stand alone scan tool. The ECU doesn't monitor 'everything' and only provides DTCs for things it measures...

agreed, you have to resolve the ignition or the spark as the initial phase of problem solving. a spark tester is a good first step...a timing light would be a better choice as you can verify the spark as well as check to make sure the timing advances with increasing engine RPM...
 
Another path you can try - look at the ECU and figure what type it is...(probably MEFI-3) there is usually a GM part number on the 'back side'. Once you know the type, do a www search and get the Delphi MEFI manual for that type...there is a wealth of how to troubleshoot data within..with and without a scan tool...
 
I have a 1999 402 Silverton with crusaders 802 xl engines. My port engine will not go much past 2000 rpm it then falls like the switch has been turned off then if I back the throttle off it resumes running. The buzzer on the dash goes off at the same time but stops once I back off.
How do I troubleshoot this and find if it’s electrical or fuel related ?

The cause is not likely electrical related, in the sense that it is stemming from a bad wire, but you likely have a sensor or mechanical issue that is putting the ECU in "safe mode."

The maddening thing about getting a scanning tool is, the early ECUs (MEFI1/2, long style that plugs in the front and back), doesn't report many, if any codes. You have to trouble shoot by looking at values, that report as gobbligook.

I'd start with your actual oil pressure, and the oil pressure switch. If the switch is bad the engine will read low oil pressure, put the engine in safe mode, and nerf the fuel pump after 1900 rpms. At 2k rpms it will immediately fall on its face.

@makomark may have knowledge to bypass the switch. You may be able to run a 12v hot to the positive terminal of the fuel pump, to interrupt the ECU attempting to shut off power to it. This isn't a long-term solution, but may help you troubleshoot.
 
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