1988 Volvo 740 GL
- Stock B21ET bottom end, 7.5:1 compression
- 398-head, stock valves, stock valvetrain except stiffer springs, some mild porting done by myself
- Volvo V camshaft
- "E-intake" from n/a k-jet engine
- Siemens Deka 630cc injectors, mounted in k-jet holes in head, walbro 255lph intank pump - running RON98
- Ported 940 cast exhaust manifold and full 3" exhaust
- Holset HY35w turbo, enlarged wastegate port, large ebay IC
- Stock LH2.4 60-2 flywheel, sinter disc and sachs racing pp - m90 gearbox
- 4.10 rear gears, truetrac differential
- External engine oil cooler and relocated filter
- Vems V3.6 with harness from vems.hu
- single coil (accel ultracoil), using stock distributor with 60-2 trigger on flywheel
- using most of the stock volvo lh2.4 sensors, only added mat-sensor and changed tps.
- Lower springs, 25mm swaybars front+rear, yellow koni shocks up front and wagon shocks in the rear.
After fire in interior (see "What has happened this far") I've not been able to communicate with the ecu. Engine runs fine, vems has no apparent problems controling it. Have tested several profilic and ftdi adapters, straight serial connection, different versions of vemstune, different versions of windows, many different com-port settings and tested adapters in terminal with pin 2 and 3 jumpered. Have also tried jumping tx/rx on ecu side to get it into bootloader mode. Wiring has been checked and tx/rx and ground are all good.
- Can you check RS232 DSUB9F/pin5 GND continuity to EC36/26 ?
- (EC18/17 is NOT always GND, eg EC18/17=2nd WBO2 heater in dual-wbo2 ECU, and some other cases)
- in case of any problem: the RX and TX would be nice to list explicitely also, just in case..
- EC18/14 = DSUB9F/pin3 ??
- EC18/15 = DSUB9F/pin2 ??
-Have checked, and have continuity between DSUB9F/pin5 and EC36/26. Even tried to ground DSUB9F/pin5 to sensor ground on the car chassis.
-EC18/14 = DSUB9F/pin3 - Yes, this is correctly wired
-EC18/15 = DSUB9F/pin2 - Yes, this is also correct.
My suspicion is that the computer (notebook + USB-RS232 adapter ?) that was connected to vems during the small interior fire somehow damaged the rs232 circut inside vems box.
- A bit weird, because the RS232 circuit proved to be very "tolerant" (max232 failure is almost unheard of; but not impossible of course).
- Do you have saved config (or vemslog) from earlier ?
- so no big deal if config cannot be recovered during repair/replacement ?
-Yes, I have a saved config. No problem if config from ecu is lost.
What has happened this far:
Started project with 1996 Volvo 940 with original low pressure turbo engine (b230fk). Messed around with lh2.4, the original engine management system and upgraded turbo, head, injectors/maf and all the usual bolt-ons. Began running e85 and upped the boost to 32psi on stock internals. Lasted about two months before it decided to let go. The b230fk was then replaced with a low compression b21et bottom end, still using the cars original engine management system.
In the fall of 2014 I switched to vems, a fairly simple process when the engine already had all the lh2.4 sensors. Used a twinshield harness from vems.hu, added a mat-sensor and changed tps from switch to potmeter type.
Sadly, in august 2015, the car caught fire somwhere in the heater fan/ventilation area and some of the interior melted and filled with soot. Water and a powder fire extinghuiser was used to put out the fire. Engine, vems ecu and drivetrain survived and was salvaged before the car was wrecked.
The components sat in my garage for about a year before being installed in the 740. A new twinshield harness was used, as the old one had molten interior on it (and I forgot to remove it - doh). Engine fired right up and runs just like it did in the 940.