1991_RS

Simple question - where does the VATS decoding take place? This is my 2nd F-body with VATS issues. Both cars had new (used) ECMs installed. BOTH cars wouldn't start due to the VATS after the ECM was changed.

With the first car, I can't be sure VATS was working as the prev owner had yanked the ECM and tried installing one from a V-6 Sunfire. That's why I had to change it. This time around, I'm changing engines, so I needed a different ECM. This car DID run before swapping engines, so I know for a fact that the VATS system was working earlier.

Is the VATS decoding actually done inside the ECM with the "VATS module" only taking care of the start enable? Why else would changing the ECM affect the VATS working correctly?

Tuned Performance

iTrader: (92)

post #5

https://www.thirdgen.org/forums/engi...s-problem.html

your key pellet is matched to the passkey module. the module sends the signal too the ecm. two parts of a vats system crank disable and injector disable.

https://www.thirdgen.org/vats_passkey_system

https://www.thirdgen.org/forums/elec...-start-my.html

1991_RS

Thanks, but I understand the "how". It's the actual "where" that I'm wondering about.

From what Oz wrote and what the VATS tech article says, I shouldn't have any problems, but obviously, that's not the case. I can jump the start enable (or even just ground the VATS input wire to trip the relay) and it will allow the car to turn over. Put a noid light on the injector and I get nothing. The car started and ran (although the engine was junk) before we swapped motor & ECM. That tells me the VATS isn't sending a signal. Hence, the question of "where" the resistor is really decoded.

Tuned Performance

iTrader: (92)

the resistor is decoded in the passkey module. If the passkey module does not see the correct resistance with in tolerance it will not send a hz signal to the ecm.

BigBadLou

iTrader: (3)

The "decoding" takes place in the dash, in the VATS module. You can move the engines and ECM's around all day but it won't affect VATS functionality.

I understand your confusion very well: if your engine ran before, how come it doens't run now?
Any chance your old ECM had VATS disabled? (you can install a new chip without VATS) Meaning that your VATS might have not worked before but your ECM just didn't care?

Lou

1991_RS

Lou - that never crossed my mind. When I had the gauge cluster out, I noticed some paint pen writing on it - a year & mileage - so maybe someone did that.

How often do people have the entire VATS go bad? This would be my 2nd car of only 2 that I've bought that had a bad VATS module!

BigBadLou

iTrader: (3)

When VATS goes bad, it's not necessarily the entire thing. It can be the contact in the ignition cylinder, it can be the wire in the steering column, it could potentially be even the box itself.

Why they go bad so often? Silly question, easy answer: because you own a Chevy!

1991_RS

OK, so I have a VATS bypass circuit in place. Hopefully, it will be temporary until I get an EPROM made without VATS - but until then, it's the same kind I used on my 91 RS without problems.

Anyway, I've got the bypass hooked up with the 30hz signal going to the blue wire on the ECM shown as crank enable (F10). That alone didn't enable the starter, so we grounded the crank relay by the driver's kick panel to get the starter to work. Still getting no pulse - checked both sides with a noid light. Wondering if the 7730 ECM is looking for 50hz signal instead or if there's another place we are supposed to wire the bypass to.

Any suggestions? Just looking to get it running so we can troubleshoot everything. Then, we'll work on a new eprom chip.

Tuned Performance

iTrader: (92)

are you getting power to the black/ pink or black/green wires on the injector with just the key on not cranking ? The injector 1 and 2 may not be getting power. I think the older vats 89-92 are all 30hz f10 on the yellow ecm connector.


Pink and Pink with blk. stripe Needs to be fused from the fuse block.

1991_RS

Is that on the white connector labeled A to R? IF so, I have 12.0 v on both pink wires. Remember that I'm using the original harness & ECM from the donor engine and had to do quite a bit of repinning to that connector and the one on the driver's firewall.

Speaking of the A-R harness, I've got 2 wires that were on the TPI one that have no "home" - one's the 4k VSS signal for TPI Speedo (Thank you T-P for setting me straight on that concept!) and the other is (I think) the MAP sensor ground - can't quite remember that one & I'm not with the car now. Should the 2nd one get hooked up somewhere?

Tuned Performance

iTrader: (92)

The Map black wire is the ground it splices in the harness with the coolant temp sensor and is grounded on the back of the passenger side cylinder head. The 4k signal to the speedo that will be determined if you are wanting to get the memcal reprogramed to optical and use the tbi vss and buffer or change to a 4k vss directly to the 730 ecm.

Tuned Performance

iTrader: (92)

one other thing to consider, I know you said the car will pop off with starting fluid so that quickly confirms spark. the 4 wire connector out of the distributor sends a signal back to the ecm make sure the connection is good at the distributor.

1991_RS

Ok, since it seems like I have everything else working except the injectors & the cranking (until we grounded the crank relay), it seems to point to a vats issue, right?

I checked power at the injectors and I've got good power there. I also checked continuity from the grounds on the injectors back to the ECM and they're good. I made sure I've got a good ground to both the engine and the body. All the fuses in the main fuse panel tested good (meter, not just by looks).

Our vats override module is outputting 31.2 Hz at 50.0% duty. Is that close enough to the 30 Hz to work? (Just for kicks, I checked the car's disconnected vats circuit and it's outputting 1052 Hz with the key that used to run the car!)

Is it possible the ECM isn't working? How can I tell?

RBob

iTrader: (1)

VATS input is from 20 Hz to 40 Hz, you are right in the middle. We use 30 Hz on our ECM benches. A DVM should show 2.5 volts on that signal into the ECM.

It is likely that the ECM is bad. Not necessarily the VATs input, but the chip that handles the injector PW.

RBob.

Tuned Performance

iTrader: (92)

Thanks for all the information Rbob

1991_RS

Am I correct to assume that there's no practical way for me to test the ECM short of swapping it out with another one?

I'm checking the yards around here (W. Mich.) to see if they have one. No luck so far at the local one. Will check a few more farther out tomorrow.

If I can't locate one locally, I'll probably have to order one from tunedperformance. I've found a few that only have the 4 sockets in them. I thought all 7730s were the same...

Tuned Performance

iTrader: (92)

1227730 16196344 ,16198262 any of these numbers here is a application list

Year Make Model Engine
1993 CHEVROLET BERETTA GT V6 3.1L 189cid GAS FI N Engine VIN = T
1993 CHEVROLET BERETTA GTZ V6 3.1L 189cid GAS FI N Engine VIN = T
1993 CHEVROLET BERETTA V6 3.1L 189cid GAS FI N Engine VIN = T
1993 CHEVROLET CAVALIER RS V6 3.1L 189cid GAS FI N Engine VIN = T
1993 CHEVROLET CAVALIER Z24 V6 3.1L 189cid GAS FI N Engine VIN = T
1993 CHEVROLET CORSICA LT V6 3.1L 189cid GAS FI N Engine VIN = T
1993 PONTIAC SUNBIRD LE L4 2.0L 122cid GAS FI N Engine VIN = H
1993 PONTIAC SUNBIRD SE L4 2.0L 122cid GAS FI N Engine VIN = H
1993 PONTIAC SUNBIRD GT V6 3.1L 189cid GAS FI N Engine VIN = T
1993 PONTIAC SUNBIRD LE V6 3.1L 189cid GAS FI N Engine VIN = T
1993 PONTIAC SUNBIRD SE V6 3.1L 189cid GAS FI N Engine VIN = T
1992 CHEVROLET BERETTA GT V6 3.1L 189cid GAS FI N Engine VIN = T
1992 CHEVROLET BERETTA GTZ V6 3.1L 189cid GAS FI N Engine VIN = T
1992 CHEVROLET BERETTA V6 3.1L 189cid GAS FI N Engine VIN = T
1992 CHEVROLET CAMARO RS V6 3.1L 189cid GAS FI N Engine VIN = T
1992 CHEVROLET CAMARO Z28 V8 5.0L 305cid GAS FI N Engine VIN = F
1992 CHEVROLET CAMARO Z28 V8 5.7L 350cid GAS FI N Engine VIN = 8
1992 CHEVROLET CAVALIER RS V6 3.1L 189cid GAS FI N Engine VIN = T
1992 CHEVROLET CAVALIER Z24 V6 3.1L 189cid GAS FI N Engine VIN = T
1992 CHEVROLET CORSICA LT V6 3.1L 189cid GAS FI N Engine VIN = T
1992 PONTIAC FIREBIRD V6 3.1L 189cid GAS FI N Engine VIN = T
1992 PONTIAC FIREBIRD FORMULA V8 5.0L 305cid GAS FI N Engine VIN = F
1992 PONTIAC FIREBIRD TRANS AM V8 5.0L 305cid GAS FI N Engine VIN = F
1992 PONTIAC FIREBIRD TRANS AM GTA V8 5.0L 305cid GAS FI N Engine VIN = F
1992 PONTIAC FIREBIRD FORMULA V8 5.7L 350cid GAS FI N Engine VIN = 8
Year Make Model Engine
1992 PONTIAC FIREBIRD TRANS AM V8 5.7L 350cid GAS FI N Engine VIN = 8
1992 PONTIAC FIREBIRD TRANS AM GTA V8 5.7L 350cid GAS FI N Engine VIN = 8
1992 PONTIAC SUNBIRD LE L4 2.0L 122cid GAS FI N Engine VIN = H
1992 PONTIAC SUNBIRD SE L4 2.0L 122cid GAS FI N Engine VIN = H
1992 PONTIAC SUNBIRD GT V6 3.1L 189cid GAS FI N Engine VIN = T
1992 PONTIAC SUNBIRD SE V6 3.1L 189cid GAS FI N Engine VIN = T
1991 CHEVROLET BERETTA GT V6 3.1L 189cid GAS FI N Engine VIN = T
1991 CHEVROLET BERETTA GTZ V6 3.1L 189cid GAS FI N Engine VIN = T
1991 CHEVROLET BERETTA V6 3.1L 189cid GAS FI N Engine VIN = T
1991 CHEVROLET CAMARO RS V6 3.1L 189cid GAS FI N Engine VIN = T
1991 CHEVROLET CAMARO Z28 V8 5.0L 305cid GAS FI N Engine VIN = F
1991 CHEVROLET CAMARO Z28 V8 5.7L 350cid GAS FI N Engine VIN = 8
1991 CHEVROLET CAVALIER RS V6 3.1L 189cid GAS FI N Engine VIN = T
1991 CHEVROLET CAVALIER Z24 V6 3.1L 189cid GAS FI N Engine VIN = T
1991 CHEVROLET CORSICA LT V6 3.1L 189cid GAS FI N Engine VIN = T
1991 PONTIAC 6000 LE V6 3.1L 189cid GAS FI N Engine VIN = T
1991 PONTIAC 6000 SE V6 3.1L 189cid GAS FI N Engine VIN = T
1991 PONTIAC FIREBIRD V6 3.1L 189cid GAS FI N Engine VIN = T
1991 PONTIAC FIREBIRD FORMULA V8 5.0L 305cid GAS FI N Engine VIN = F
1991 PONTIAC FIREBIRD TRANS AM V8 5.0L 305cid GAS FI N Engine VIN = F
1991 PONTIAC FIREBIRD TRANS AM GTA V8 5.0L 305cid GAS FI N Engine VIN = F
1991 PONTIAC FIREBIRD FORMULA V8 5.7L 350cid GAS FI N Engine VIN = 8
1991 PONTIAC FIREBIRD TRANS AM V8 5.7L 350cid GAS FI N Engine VIN = 8
1991 PONTIAC FIREBIRD TRANS AM GTA V8 5.7L 350cid GAS FI N Engine VIN = 8
1991 PONTIAC SUNBIRD LE L4 2.0L 122cid GAS FI N Engine VIN = K
Year Make Model Engine
1991 PONTIAC SUNBIRD SE L4 2.0L 122cid GAS FI N Engine VIN = K
1991 PONTIAC SUNBIRD L4 2.0L 122cid GAS FI N Engine VIN = K
1991 PONTIAC SUNBIRD GT V6 3.1L 189cid GAS FI N Engine VIN = T
1991 PONTIAC SUNBIRD LE V6 3.1L 189cid GAS FI N Engine VIN = T
1991 PONTIAC SUNBIRD SE V6 3.1L 189cid GAS FI N Engine VIN = T
1990 CHEVROLET BERETTA GT V6 3.1L 189cid GAS FI N Engine VIN = T
1990 CHEVROLET BERETTA V6 3.1L 189cid GAS FI N Engine VIN = T
1990 CHEVROLET CAMARO RS V6 3.1L 189cid GAS FI N Engine VIN = T
1990 CHEVROLET CAMARO IROC-Z V8 5.0L 305cid GAS FI N Engine VIN = F
1990 CHEVROLET CAMARO IROC-Z V8 5.7L 350cid GAS FI N Engine VIN = 8
1990 CHEVROLET CAVALIER Z24 V6 3.1L 189cid GAS FI N Engine VIN = T
1990 CHEVROLET CAVALIER V6 3.1L 189cid GAS FI N Engine VIN = T
1990 CHEVROLET CELEBRITY V6 3.1L 189cid GAS FI N Engine VIN = T
1990 CHEVROLET CORSICA LT V6 3.1L 189cid GAS FI N Engine VIN = T
1990 CHEVROLET CORSICA LTZ V6 3.1L 189cid GAS FI N Engine VIN = T
1990 PONTIAC 6000 LE V6 3.1L 189cid GAS FI N Engine VIN = T
1990 PONTIAC 6000 SE V6 3.1L 189cid GAS FI N Engine VIN = T
1990 PONTIAC FIREBIRD V6 3.1L 189cid GAS FI N Engine VIN = T
1990 PONTIAC FIREBIRD FORMULA V8 5.0L 305cid GAS FI N Engine VIN = F
1990 PONTIAC FIREBIRD TRANS AM V8 5.0L 305cid GAS FI N Engine VIN = F
1990 PONTIAC FIREBIRD TRANS AM GTA V8 5.0L 305cid GAS FI N Engine VIN = F
1990 PONTIAC FIREBIRD FORMULA V8 5.7L 350cid GAS FI N Engine VIN = 8
1990 PONTIAC FIREBIRD TRANS AM V8 5.7L 350cid GAS FI N Engine VIN = 8
1990 PONTIAC FIREBIRD TRANS AM GTA V8 5.7L 350cid GAS FI N Engine VIN = 8
1990 PONTIAC SUNBIRD GT L4 2.0L 122cid GAS FI N Engine VIN = K
Year Make Model Engine
1990 PONTIAC SUNBIRD LE L4 2.0L 122cid GAS FI N Engine VIN = K
1990 PONTIAC SUNBIRD SE L4 2.0L 122cid GAS FI N Engine VIN = K
1990 PONTIAC SUNBIRD GT L4 2.0L 122cid GAS FI T Engine VIN = M
1990 PONTIAC SUNBIRD LE L4 2.0L 122cid GAS FI T Engine VIN = M
1989 BUICK CENTURY CUSTOM V6 2.8L 173cid GAS FI N Engine VIN = W
1989 BUICK CENTURY LIMITED V6 2.8L 173cid GAS FI N Engine VIN = W
1989 CHEVROLET BERETTA GT V6 2.8L 173cid GAS FI N Engine VIN = W
1989 CHEVROLET BERETTA V6 2.8L 173cid GAS FI N Engine VIN = W
1989 CHEVROLET CAVALIER Z24 V6 2.8L 173cid GAS FI N Engine VIN = W
1989 CHEVROLET CAVALIER V6 2.8L 173cid GAS FI N Engine VIN = W
1989 CHEVROLET CELEBRITY V6 2.8L 173cid GAS FI N Engine VIN = W
1989 CHEVROLET CORSICA LTZ V6 2.8L 173cid GAS FI N Engine VIN = W
1989 CHEVROLET CORSICA V6 2.8L 173cid GAS FI N Engine VIN = W
1989 OLDSMOBILE CUTLASS CIERA CRUISER V6 2.8L 173cid GAS FI N Engine VIN = W
1989 OLDSMOBILE CUTLASS CIERA CRUISER SL V6 2.8L 173cid GAS FI N Engine VIN = W
1989 OLDSMOBILE CUTLASS CIERA SL V6 2.8L 173cid GAS FI N Engine VIN = W
1989 OLDSMOBILE CUTLASS CIERA V6 2.8L 173cid GAS FI N Engine VIN = W
1989 PONTIAC 6000 LE V6 2.8L 173cid GAS FI N Engine VIN = W
1989 PONTIAC 6000 SE V6 2.8L 173cid GAS FI N Engine VIN = W
1989 PONTIAC 6000 STE V6 3.1L 189cid GAS FI N Engine VIN = T
1988 BUICK CENTURY CUSTOM V6 2.8L 173cid GAS FI N Engine VIN = W
1988 BUICK CENTURY ESTATE WAGON V6 2.8L 173cid GAS FI N Engine VIN = W
1988 BUICK CENTURY LIMITED V6 2.8L 173cid GAS FI N Engine VIN = W
1988 CADILLAC CIMARRON V6 2.8L 173cid GAS FI N Engine VIN = W
1988 CHEVROLET BERETTA L4 2.0L 122cid GAS FI N Engine VIN = 1
Year Make Model Engine
1988 CHEVROLET BERETTA V6 2.8L 173cid GAS FI N Engine VIN = W
1988 CHEVROLET CAVALIER RS V6 2.8L 173cid GAS FI N Engine VIN = W
1988 CHEVROLET CAVALIER Z24 V6 2.8L 173cid GAS FI N Engine VIN = W
1988 CHEVROLET CAVALIER V6 2.8L 173cid GAS FI N Engine VIN = W
1988 CHEVROLET CELEBRITY V6 2.8L 173cid GAS FI N Engine VIN = W
1988 CHEVROLET CORSICA L4 2.0L 122cid GAS FI N Engine VIN = 1
1988 CHEVROLET CORSICA V6 2.8L 173cid GAS FI N Engine VIN = W
1988 OLDSMOBILE CUTLASS CIERA BROUGHAM V6 2.8L 173cid GAS FI N Engine VIN = W
1988 OLDSMOBILE CUTLASS CIERA CRUISER V6 2.8L 173cid GAS FI N Engine VIN = W
1988 OLDSMOBILE CUTLASS CIERA CRUISER BROUGHAM V6 2.8L 173cid GAS FI N Engine VIN = W
1988 OLDSMOBILE CUTLASS CIERA SL V6 2.8L 173cid GAS FI N Engine VIN = W
1988 OLDSMOBILE CUTLASS CIERA V6 2.8L 173cid GAS FI N Engine VIN = W
1988 PONTIAC 6000 LE V6 2.8L 173cid GAS FI N Engine VIN = W
1988 PONTIAC 6000 SE V6 2.8L 173cid GAS FI N Engine VIN = W
1988 PONTIAC 6000 STE V6 2.8L 173cid GAS FI N Engine VIN = W
1988 PONTIAC 6000 V6 2.8L 173cid GAS FI N Engine VIN = W
1988 PONTIAC 6000 STE V6 3.1L 189cid GAS FI N Engine VIN = T
1987 BUICK CENTURY CUSTOM V6 2.8L 173cid GAS FI N Engine VIN = W
1987 BUICK CENTURY ESTATE WAGON V6 2.8L 173cid GAS FI N Engine VIN = W
1987 BUICK CENTURY LIMITED V6 2.8L 173cid GAS FI N Engine VIN = W
1987 BUICK SKYHAWK CUSTOM L4 2.0L 122cid GAS FI N Engine VIN = 1
1987 BUICK SKYHAWK LIMITED L4 2.0L 122cid GAS FI N Engine VIN = 1
1987 BUICK SKYHAWK SPORT L4 2.0L 122cid GAS FI N Engine VIN = 1
1987 CADILLAC CIMARRON V6 2.8L 173cid GAS FI N Engine VIN = W
1987 CHEVROLET BERETTA L4 2.0L 122cid GAS FI N Engine VIN = 1
Year Make Model Engine
1987 CHEVROLET BERETTA V6 2.8L 173cid GAS FI N Engine VIN = W
1987 CHEVROLET CAVALIER CS L4 2.0L 122cid GAS FI N Engine VIN = 1
1987 CHEVROLET CAVALIER RS L4 2.0L 122cid GAS FI N Engine VIN = 1
1987 CHEVROLET CAVALIER L4 2.0L 122cid GAS FI N Engine VIN = 1
1987 CHEVROLET CAVALIER CS V6 2.8L 173cid GAS FI N Engine VIN = W
1987 CHEVROLET CAVALIER RS V6 2.8L 173cid GAS FI N Engine VIN = W
1987 CHEVROLET CAVALIER Z24 V6 2.8L 173cid GAS FI N Engine VIN = W
1987 CHEVROLET CAVALIER V6 2.8L 173cid GAS FI N Engine VIN = W
1987 CHEVROLET CELEBRITY V6 2.8L 173cid GAS FI N Engine VIN = W
1987 CHEVROLET CORSICA L4 2.0L 122cid GAS FI N Engine VIN = 1
1987 CHEVROLET CORSICA V6 2.8L 173cid GAS FI N Engine VIN = W
1987 OLDSMOBILE CUTLASS CIERA BROUGHAM V6 2.8L 173cid GAS FI N Engine VIN = W
1987 OLDSMOBILE CUTLASS CIERA CRUISER V6 2.8L 173cid GAS FI N Engine VIN = W
1987 OLDSMOBILE CUTLASS CIERA CRUISER BROUGHAM V6 2.8L 173cid GAS FI N Engine VIN = W
1987 OLDSMOBILE CUTLASS CIERA S V6 2.8L 173cid GAS FI N Engine VIN = W
1987 OLDSMOBILE CUTLASS CIERA SL V6 2.8L 173cid GAS FI N Engine VIN = W
1987 OLDSMOBILE CUTLASS CIERA V6 2.8L 173cid GAS FI N Engine VIN = W
1987 OLDSMOBILE FIRENZA LC L4 2.0L 121cid GAS FI N Engine VIN = 1
1987 OLDSMOBILE FIRENZA LX L4 2.0L 121cid GAS FI N Engine VIN = 1
1987 OLDSMOBILE FIRENZA S L4 2.0L 121cid GAS FI N Engine VIN = 1
1987 OLDSMOBILE FIRENZA L4 2.0L 121cid GAS FI N Engine VIN = 1
1987 OLDSMOBILE FIRENZA GT V6 2.8L 173cid GAS FI N Engine VIN = W
1987 PONTIAC 6000 LE V6 2.8L 173cid GAS FI N Engine VIN = W
1987 PONTIAC 6000 SE V6 2.8L 173cid GAS FI N Engine VIN = W
1987 PONTIAC 6000 STE V6 2.8L 173cid GAS FI N Engine VIN = W
1987 PONTIAC 6000 V6 2.8L 173cid GAS FI N Engine VIN = W

Tuned Performance

iTrader: (92)

Just the steps I told you before check your ecm power and grounds see if you can get the ecm to go into field service mode bye jumping the a to b at the aldl and make sure you have continuity for the distributor reference wires to the ecm. You have already verified spark so chances are the icm is good.

1991_RS

Tunedperformance - do I need to have pins M & E wired together for the A-B jumper to work? Just asking because I haven't gotten around to that yet.

Also, once I wire M & E together, will a standard scanner pull codes (& do I enter the '91 motor info ) or am I destined to no-scanning with this swap?

Tuned Performance

iTrader: (92)

m and e of the aldl? no just turn the key to the accessory position and jumper the a to b terminal of the aldl.

http://www.obd-codes.com/faq/read-gm...codes-free.php

not a 100 % way to test the ecm but if there is no communication It would be more than likely junk.

RBob

iTrader: (1)

If you have the Sunfire MEMCAL try it with that one. I doubt it has VATs enabled. To do this disconnect the EST/BYPASS connector. Then see if it starts and runs. The injector firing rate will be incorrect, and it may run badly.

But at least you can see if the injectors fire.

RBob.

Mlanzo

iTrader: (1)

not hijacking here, but does a 1985 iroc with tpi have VATS, or anything similar that may give the car trouble running?

BigBadLou

iTrader: (3)

Nope.

Mlanzo

iTrader: (1)

SO IF MY CAR IS RUNNING AND THEN SHUTS OFF AFTER A WHILE ITS PROB A SENSOR I WILL BE GETTING THE WIRE FOR MY LAPTOP, SO I SHOULD BE ABLE TO FIGURE IT OUT

1991_RS

VATS began in 1989. Unless you changed the eprom to a newer one, you should not have a VATS issue.

1991_RS

Good news! I went back and double checked the wiring harness (The one going to the white one pins A-R) and there was a pink one that we had to disconnect because it didn't match up to the car. One of the schematics had it listed as some type of ground. I found a better diagram that listed it as ECM Power (A6) going to a fused ignition.

We put power to that and now we have pulse (verified with noid). Still doesn't start though. Wondering if gas is too skunky for it. There's 6 gal of old gas and 6 gal of fresh gas in it. (Any idea how long it takes the pump to circulate fresh fuel through the system if I jump the pump relay?)

Anything else that might be causing it not to start that we're overlooking? (Yeah, I know, diagnosing over a forum is as easy as getting a politician to tell the truth!)

Tuned Performance

iTrader: (92)

you could have stuck injectors, fuel start to varnish and breakdown after 90 days if not treated with a stabilizer. if you jumper the fuel pump relay fuel will circulate through the rail and back to the tank. I assume you changed the pump as part of your swap ?

1991_RS

Yes (and we ended up replacing sending unit as someone did the "cut and patch" replacement earlier).

How long (roughly) does it take to recirculate fully? Are we talking a minute or two or several minutes or more?

Tuned Performance

iTrader: (92)

yes a few min would circulate through the new fuel