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86' 740 Fuel Delivery Problem

Help, Advice, Owners' Discussion and DIY Tutorials on all Volvo's "mid era" rear wheel drive Volvos.

1975 - 1993 240
1983 - 1992 740
1982 - 1991 760
1986 - 1991 780
1990 - 1998 940
1990 - 1998 960
1997 - 1998 V90/S90

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93Regina
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Re: 86' 740 Fuel Delivery Problem

Post by 93Regina »

waynegarbo wrote:If you mean 87/1, with 87/2, and 30 and start, No.
In your third post, "but there is normal pressure reading from the jump at relay terminals 30-87/2."

With a normal pressure reading, does vehicle start?

waynegarbo
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Post by waynegarbo »

No I was only testing for fuel pressure from the pumps...then I was informed by my former mechanic to try a "three wire" jump within the relay box. 87/1-87/2-30-start, to no avail....

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93Regina
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Post by 93Regina »

waynegarbo wrote:No....
Let's see, vehicle has,'

1. Spark
2. Fuel Pressure, when jumpered

but, when vehicle has fuel pressure, and then the key is switched to on, then start, it will not start...is this correct?

If true, then remove the fuel return hose at fuel-pressure-regulator, and hook another short hose on FPR, with a bottle below to catch fuel when you activate jumper wire to engage fuel pump...have someone watch the bottle...is there fuel there?

waynegarbo
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Post by waynegarbo »

No this is not correct, fuel pressure is not engaged through the ignition system. but I get fuel pressure when I remove the relay and jump with only the 30-87/2. So, former mechanic added a third wire at 87/1, for a three way jump, with no relay intact, then we tried to start, and nadda...I have a new
fuel pressure regulator and it does not leak...I already have tried starting the car with the return line unplugged to see of any fuel delivery and no.
right now I believe I have no ecu ground. but I will try what you suggest as I believe, yes, fuel should come out the short hose but what if it does? It should but that doesn't correct my no fuel delivery by ignition

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93Regina
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Post by 93Regina »

waynegarbo wrote:So.......................
When trouble shooting a dead EFI, one examines two areas:

1. Correct Spark
2. Fuel Pressure

Item one has not been established, and item two has not been established.

Having spark, is not the same as having correct spark. Having fuel pressure is not the same as having fuel pressure when engine is cranked.

So, when fuel comes out of the FPR's return line to tank, when hot-wired, then one re-insert's vehicle's return-hose to FPR, and then see if engine starts with hot-wire engaged.

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Post by waynegarbo »

Next time to establish what your saying I'll open up the return line on #2. #1 was overlooked because other than seeing spark, and seeing my tach needle move on start I overlooked the spark issue, until friday night I jiglled the dist connector while hitting my remote starter. the car started but was cutting out and I had to keep messing with the connector. Sat I replaced the dist and it fixed the problem.

How do you check for correct spark other than doing the hall sensor test?

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93Regina
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Post by 93Regina »

waynegarbo wrote:How do you check for correct spark?
Check all three timing-belt sprockets (cam, distributor's, and crank) for correct alignment..or use a timing light.

Assuming someone has not messed with distributor's position.

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Post by waynegarbo »

well it's been about a month now...timing adjusted looks fine...this car continues to have idle problems...and I am not completely dialed in yet...i did pull the IAC valve sprayed it and tested it, put it back in...but somethings still fishy about this....my wires have come apart three times upon pulling them to check the connections and pluggs...my pluggs are burning normal, although I still want to clean them, they are less than a year old...I was thinking of getting another IAC and I want to pull and check the coolent temp sensor and I also want to adjust the valves. I've had this car four years
there's 200k and I bet no one has adjusted the valves

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Post by 93Regina »

waynegarbo wrote:IAC
The computer does the adjustment, so if IAC is working, that's all.

Valves - Do a compression check first

MAF - I would think there are some tests that could be done, but I'd have to look for the specifics. If engine is loping, it may be a defective MAF/AMM. I'll look around later. LH 2.2 right?

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93Regina
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Post by 93Regina »

waynegarbo wrote: IAC valve
Test Procedure

Air Mass Meter Diagnosis.

Wiring Diagram

Some Details, if you speak another language.
Luftmassmätare, I think means AMM

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