Nate1647545505 Posted January 20, 2004 Report Share Posted January 20, 2004 Well, we stumped our dealerships. Back to the truck..98 Chevy 2500 This we know: -Its a 350 -Its an electronically advanced Distributor -LS1m Scan Tool reads data accurately. -No Compression Leaks, all new sensors, complete test down. -We have to advance the timing to start the truck, 8 degrees This we are unsure of: -The Cam Position (stock) Haynes states 6 o'clock along with Chilton’s, All data states 12 o'clock. When we ran it at 12, it wouldn’t even start, it was firing on the intake stroke. We are at 6 which is at complete TDC, a kit was used to verify. It will start and run very LEAN with misfires. (Advanced Timing) -The effects of the cam The cam is not an extreme lift or duration cam In open loop the truck starts up, no code is set until the car has warmed up, and it cycles to closed. First off, Is it normal for cammed engines to advance timing during cranking (Centrifugal Advance Distributors did’nt advance until the engine was started?) Second, Is this Ignition System HEI? If anyone could enlighten me on technical names, that would aid our search. As far as DTCs, We are getting a Crank / Camshaft Position Code. Is there a CASE learn procedure for this? I’m taking a shot in the dark, but would the duration change from the cam cause this code? If so, would delaying the current or voltage impulse by a static time be a possible fix, accompanied by a MAF mod to compensate for any A/F conditions? [ 21. January 2004, 08:12 PM: Message edited by: bavarian built hot rod ] Quote Link to comment Share on other sites More sharing options...
ridenred27 Posted January 20, 2004 Report Share Posted January 20, 2004 does the timing chain look like the LT1 chain. second look closely at the intake those are good for cracking and leaking. oh and one more thing is it a seqential port injection. just tring to get a picture of the engine design Quote Link to comment Share on other sites More sharing options...
Nate1647545505 Posted January 20, 2004 Author Report Share Posted January 20, 2004 it is the VORTEC system (still researching) [ 20. January 2004, 09:56 PM: Message edited by: bavarian built hot rod ] Quote Link to comment Share on other sites More sharing options...
Tractor Posted January 21, 2004 Report Share Posted January 21, 2004 The 98 model year used an EDI (Enhanced Distributer Ignition) system. Its part of the Central SFI(Sequencial Fuel Injection) system. I'm looking through my manuals and the EDI system uses a CPS (camshaft position sensor). Its possible that this is not in the correct position. The manual states that the CPS is used by the ECM to find the crank/cam position and will through engine codes, but probably won't prevent the vehicle from running (doesn't say how good.) My haynes manual for that truck/engine says when installing the cam align the dowl pin with the 9 o'clock position Page 2A-16 first paragraph and illustration 11.25. Quote Link to comment Share on other sites More sharing options...
Nate1647545505 Posted January 21, 2004 Author Report Share Posted January 21, 2004 thanks man, I'm going to take a trip up to Cleveland this weekend to see what can be done Quote Link to comment Share on other sites More sharing options...
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