IPD sale XeMODeX - Experts in Volvo Electronics
Did you know? 🤔
Logged in users can get email notification of topic replies Log in or register (free).
Amazon Link Buy anything with this and it helps MVS!

Have to disconnect/reconnect battery to start car,immobilizer problem?

Help, Advice and DIY Tutorials on Volvo's extremely popular car line -- Volvo's 1990s "bread and butter" cars -- powered by the ubiquitous and durable Volvo inline 5-cylinder engine.

1992 - 1997 850, 850 R, 850 T5-R, 850 T5, 850 GLT
1997 - 2000 S70, S70 AWD
1997 - 2000 V70, V70 AWD
1997 - 2000 V70-XC
1997 - 2004 C70

hufilm99
Posts: 2
Joined: Fri Jul 08, 2016 12:03 am
Year and Model: 1999 C70
Location: San Diego
Has thanked: 0
Been thanked: 0
United States of America
hufilm99

Have to disconnect/reconnect battery to start car,immobilizer problem?

Post by hufilm99 » Fri Jul 08, 2016 12:10 am

Hey guys and gals I have a real problem I can't seem to figure out. My car won't start constantly. If I let the car sit for a period of time, say over night, it will start right up. When I go to start it a second time if not much time has passed the car won't start. The car will crank but won't turn over. It seems like the car isn't getting fuel pressure so I check the fuel relay and fuel pump and they seem to be working fine. Also, the car has a new battery so no problem there. Today I just discovered a trick to start the car that might point towards the problem. If I disconnect the battery for about a minute then reconnect the car starts every time. Does this make sense to anyone? I'm thinking now that it's some problem with the immobilizer but I'm not getting any codes on the dash to tell me this is the problem. Has this happened to anyone else? Sorry for the long post. Look forward to hearing from the group.

B

User avatar
abscate
MVS Moderator
Posts: 21507
Joined: Sun Feb 17, 2013 5:54 pm
Year and Model: 99T5 ,99S70,2005V70
Location: NYC, ALBANY NY
Has thanked: 335 times
Been thanked: 1035 times
Trinidad & Tobago
abscate

Re: Have to disconnect/reconnect battery to start car,immobilizer problem?

Post by abscate » Fri Jul 08, 2016 8:27 am

An immobiliser trigger does not set an engine code. You might have a engine coolant temperature (ECT) sensor issue that is dumping excess fuel into the engine for a start - there is info here in the VRD on testing that unit for correct resistance.

Diagnosing by symptom is rarely successful on these cars - you have to break out a systematic approach to evaluating spark, fuel, air, timing and compression and find out which one(s) are missing
Empty Nester
A Captain in a Sea of Estrogen
1999-V70-T5M56 2005-V70-M56 1999-S70 VW T4 BMW
Link to Maintenance record thread
Link To Volvo Glossary

hufilm99
Posts: 2
Joined: Fri Jul 08, 2016 12:03 am
Year and Model: 1999 C70
Location: San Diego
Has thanked: 0
Been thanked: 0
United States of America
hufilm99

Re: Have to disconnect/reconnect battery to start car,immobilizer problem?

Post by hufilm99 » Fri Jul 08, 2016 11:27 am

I did a number of checks and I know it's a fuel issue. When testing the car from a bad start, I noticed that the engine wasn't getting any fuel pressure. I swapped the fuel pump relay and fuel pump but discover the problem is still there. Basically the car will only start after sitting for a long time or disconnecting the batter resetting a sensor in the car. The car will reliably start if you detach the battery cable. So there has to be a system in the car that is preventing fuel from getting to the engine once the system "sets" its self if that makes sense. I've been reading through a number of forums but I can't seem to find anyone with this same problem. Am convinced it's something with the anti theft system but I'm not sure where to look first.

Ozark Lee
MVS Moderator
Posts: 14798
Joined: Thu Sep 07, 2006 8:24 am
Year and Model: Many Volvos
Location: USA Midwest
Has thanked: 4 times
Been thanked: 53 times
United States of America
Ozark Lee

Re: Have to disconnect/reconnect battery to start car,immobilizer problem?

Post by Ozark Lee » Fri Jul 08, 2016 12:57 pm

The immobilizer on your car typically will let the car start but about 1 second later it will die. I believe it does that by killing the ignition but not the fuel.

Have you tried installing a jumper wire in place of the fuel pump relay? A wire between the socket positions associated with pins 15 and 87 on the relay should power the fuel pump anytime the ignition switch is on and it is a very good diagnostic tool.

Beyond that you will really need to get a scan with VIDA and DICE to see what is actually happening.

...Lee
'94 850 N/A 5 speed
'96 Platinum Edition Turbo
Previous:
1999 V70XC - Nautic Blue - Totaled while parked.
1999 V70XC - RIP - Wrecked Parts Car.
1998 S70 T5
1996 850 N/A
1989 740 GLT
1986 740 GLT
1972 142 Grand Luxe

User avatar
abscate
MVS Moderator
Posts: 21507
Joined: Sun Feb 17, 2013 5:54 pm
Year and Model: 99T5 ,99S70,2005V70
Location: NYC, ALBANY NY
Has thanked: 335 times
Been thanked: 1035 times
Trinidad & Tobago
abscate

Re: Have to disconnect/reconnect battery to start car,immobilizer problem?

Post by abscate » Fri Jul 08, 2016 6:16 pm

Me7 cuts ignition, so you have to run the fuel system diagnostic tree
Empty Nester
A Captain in a Sea of Estrogen
1999-V70-T5M56 2005-V70-M56 1999-S70 VW T4 BMW
Link to Maintenance record thread
Link To Volvo Glossary

Post Reply
  • Similar Topics
    Replies
    Views
    Last post