This what I have swapped out with my 90 744ti, fuel pump relay, fuel injection relay, power stage, fuel pressure regulator and coil. I have disconnected the air mass meter and checked all of the connections. The hall sensor has been replaced and I am getting a tach signal (tach is jumping while cranking). All of the ignition components are in good shape and the timing belt is new. The fuel pumps do not come on when the key is turned on but they will come on when the relay is jumpered. The engine will not start with the relay jumpered. I am getting fuel pressure at the rail. I am getting 12 volts to fuse 11(I checked the correct fuse but could be misstating it). I am obviously not getting the signal that turns on the pumps. My 90 740 runs fine it just has a leaky water pump therefore all the parts swapped are in good shape. Where do I go from here.



From previous post.
Last Thursday when I attempted to start my 88 745 N/A the engine caught but immediately died. It then turned over but would not start. It sat for several minutes then immediately started and I did not have any more problems until this morning. When I cranked the car it caught and died twice and then would not catch. The engine was turning over not a dead battery. It then started but I turned the engine off and it would start again. When it does start it cranks immediately and runs fine.
This is what has been done to the car recently. Plugs, cap, rotor, wires, hall sensor and timing belt. I have swapped the fuel pump and fuel injection relay from 90 740. I have also disconnected the mass meter but to no avail. It has a new battery and the connections are clean. The ground on the back of the valve cover is clean. I have not checked the one on the fuel rail but the look to be in good condition. I was going to swap the coil and check the condition of all the fuses tonight.
Does anyone have another suggestion?
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90 744ti, Airbox, K/N, Cold air, G-Valve, Dual boost control, VDO, Modified exhaust. 88 745 gle, 99 Camry

Bryan,

My "hands-on" time has been almost exclusively 240. And though much fuel and ignition stuff is shared across all 3 platforms, I think it's not the same for all years. That is, I think your '88 740 may have the LH 2.4, which didn't get to the 240 till '89. Best I can do for openers is comment on parts of your post that caught my nit-picker's eye, and offer a rare but recent and personal 240 failure that shares your symptoms (but maybe not the cause, however).

"This what I have swapped out with my 90 744ti, , power stage, fuel pressure regulator and coil."
• Terminology? I'm guessing your "fuel pump" relay is my "Fuel Injection" relay. The white one that powers the pumps, and much more: AMM and ECU for example. Your FI relay? Maybe the "Interference/Radio Suppression" relay in the engine compartment?

"The fuel pumps do not come on when the key is turned on but they will come on when the relay is jumpered. The engine will not start with the relay jumpered."
• I don't know just how you "jumpered" the relay. It has two critical outputs. The pumps are just one of them. You're saying the pumps aren't the main issue, right? You can force them on by jumpering the relay, but still no start. Give me "jumpering" details please.

"I am getting fuel pressure at the rail."
• "Residual" pressure (from when the pumps last ran) can be misleading.

"I am getting 12 volts to fuse 11(I checked the correct fuse but..."
• Fuse 1 is the main FI fuse, #11 is for tank pump. Do you have any wiring diagrams?

My recent 240 failure was the FI relay, but in a way I've never seen -- or heard of here. That white FI relay is really 2 relays in one package. The "Main" relay comes on with Key ON, to power the AMM and ECU. It also puts power on the Fuel relay coil. But it's up to the ECU to energize the Fuel relay by giving its coil a ground (as with injector control).

The ECU can ground the Fuel relay at Key ON (LH 2.4 only -- 2.2 doesn't do this) to "buzz" the pumps. And then during cranking and running, but only if it gets timing pulses from the Ignition CU.

However, none of that will happen if the first relay (or its output terminal) fails -- no AMM, no ECU, no power to the fuel relay. You can "force" the pumps, but without the AMM and ECU nothing happens.

That's what happened to our 240, and it was a "first" for me. We had to jumper from the FI relay input (terminal 30) to BOTH outputs -- 87/1 for the AMM, ECU, Injectors, Suppression relay, etc., AND to 87/2 for fuel -- the usual suspect.

On your car, I think you can check for voltage from 87/1 (Key ON) at AMM pin 5 or RSR (Radio Suppression Relay pin 2. It should be a blue/yellow wire if colors were constant over time as in 240s. My diagram is for the '93 940.

Sorry for all the rambling, but this is sort of a fishing trip at this point.

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Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.

First thank you for your response.
My 88 has L.H 2.2. The 740's did not 2.4 until late 89 as did the 240

• Terminology? I'm guessing your "fuel pump" relay is my "Fuel Injection" relay. The white one that powers the pumps, and much more: AMM and ECU for example. Your FI relay? Maybe the "Interference/Radio Suppression" relay in the engine compartment?
You are correct in regards to the terminology.

• I don't know just how you "jumpered" the relay. It has two critical outputs. The pumps are just one of them. You're saying the pumps aren't the main issue, right? You can force them on by jumpering the relay, but still no start. Give me "jumpering" details please.
My testing information came from the FAQ:
http://www.brickboard.com/FAQ/700-900/EngineFuelinjection.htm#FuelPumpandFIRelayDiagnosticTests

Jumper terminals 30 and 87/2. This makes the pumps run continuously. Which just proves that they will run and pump fuel. It was a mistake on my part thinking that the car would start by just the pumps running.

• "Residual" pressure (from when the pumps last ran) can be misleading.
No it was more than residual pressure. When I swapped the FPR I did not have it tight and fuel sprayed everywhere.

• Fuse 1 is the main FI fuse, #11 is for tank pump. Do you have any wiring diagrams?
Once again this is from the same page of the FAQ but I am getting power to fuse 1

Tip:] To check for possible fuel pump relay failure go between center of cig lighter plug and fuse 11, should be less than .5 V (<500mV)

Do you have any wiring diagrams?
The only diagrams that I have are for my 90 model and it is a sorry chiltons manual for 90-93 that I am not sure I trust.
I will check for 12v and let you know.

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90 744ti, Airbox, K/N, Cold air, G-Valve, Dual boost control, VDO, Modified exhaust. 88 745 gle, 99 Camry

Maybe a diagram here.
http://www.autoelectric.ru/auto/volvo/740/1989/740-89.htm

Walt the diagrams are great and should be a tremendous help.
Thanks.
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90 744ti, Airbox, K/N, Cold air, G-Valve, Dual boost control, VDO, Modified exhaust. 88 745 gle, 99 Camry

Thanks I will check it out.
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90 744ti, Airbox, K/N, Cold air, G-Valve, Dual boost control, VDO, Modified exhaust. 88 745 gle, 99 Camry

Another thing that's been noted here at least once is a failure in the "timing pulse" from the EZK CU to the LH ECU. This also renders the ECU useless -- no ground for the fuel relay, and no injector control either. So even with the pumps jumpered, no fuel gets squirted.

Maybe you can find this line on the Russian diagram. It should come into the LH ECU on pin 1. I haven't a clue about the '88 EZK, but later ones send the timing pulse out from pin 17 (yellow/gray wire in the '93 diagram).

With spark and fuel to the rail (with pumps forced), I think injector failure is most likely. Either no injector voltage (Suppression relay), or no ground pulses (ECU bad, lack of power to ECU, lack of timing pulses to ECU, other???)

I think something is crippling the ECU -- thus no FI relay and no injectors if pumps are forced.
--
Bruce Young
'93 940-NA (current) — 240s (one V8) — 140s — 122s — since '63.

I knew that it was centered around the F.I. relay but was lost as to where the signals came from. The Russian diagrams are fantastic and should help me trace the signals. Fortunately my fuse box will pull all of the way out which will help me to check it thoroughly.
Once again thanks for the help and I will update my progress.
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90 744ti, Airbox, K/N, Cold air, G-Valve, Dual boost control, VDO, Modified exhaust. 88 745 gle, 99 Camry