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chasing demons

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

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shegarty
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chasing demons

Post by shegarty »

So, I knew that if I posted that the problem was solved it would rear its ugly head again ... I've been chasing a hard cold (below -15ºC) start now for two years. Replaced ECT, crank and cam sensors and most recently replaced vacuum lines to the FPR. The last couple of days when it was -23ºC it started right up after a couple of cranks, to be expected in a 20 yr old vehicle. Today when it was -6ºC it refused to start. I was able to eventually get it started but as soon as I did the throttle began running away, up to 5000rpm before I killed the engine for fear of catastrophic failure. I cleaned the internals on the IAC again (done last year) and the electrical connections as well as another vacuum line (leads to relay on the fan shroud, I think its part of the regulation on the turbo) on the tree that looked like it might be split.

Still no luck, throttle continues to run away. I found that in blipping the throttle by hand that it was not returning to the idle position but could be forced back by twisting the recoil back. I have isolated this to what appears to be a vacuum assist connected to the pedal in the cabin, its not the throttle linkage in the engine bay as it returns no problem when tension is relieved on the cable. It appears that the vacuum assist is not pulling (or pushing I guess) the pedal back into the neutral idle position. Throughout this I pulled several codes at different times that all appear to be related to vacuum and idle (P1507, P1505 & P0505). Any ideas on where the vacuum line connected to the throttle goes or how I can trouble shoot this????
current - 98 S70 T5 SE (255k km)
previous - 90 745T (400k km - sold); 94 855 T5 - (206k km - blown timing idler bearing)
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rspi
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Re: chasing demons

Post by rspi »

'95 855 T-5R M, Panther - 22/28 mpg
'98 S70 GLT, Lil' Red 25/32 mpg
--------------------
Volvo's of past: '87 740 GLE, '79 262C Bertone, '78 264, 960's, '98 S70 GLT, '95 850 T-5R YellowVolvo Repair Videos
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rspi
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Re: chasing demons

Post by rspi »

Sounds like the cable is binding somewhere to me.
'95 855 T-5R M, Panther - 22/28 mpg
'98 S70 GLT, Lil' Red 25/32 mpg
--------------------
Volvo's of past: '87 740 GLE, '79 262C Bertone, '78 264, 960's, '98 S70 GLT, '95 850 T-5R YellowVolvo Repair Videos
shegarty
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Re: chasing demons

Post by shegarty »

Sounds like that to me too rspi but the fact that it is throwing codes for vacuum related issues has me wondering if it could be a lack of proper vacuum somewhere. After watching the video, I now know that the actuator I can see is related to the cruise control ... I am hoping to have some time tomorrow to look at it again.
Last edited by shegarty on Sun Jan 07, 2018 6:40 pm, edited 1 time in total.
current - 98 S70 T5 SE (255k km)
previous - 90 745T (400k km - sold); 94 855 T5 - (206k km - blown timing idler bearing)
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rspi
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Re: chasing demons

Post by rspi »

Vacuum should NOT be on the bellow under the dash when the car is off. Pull that vacuum line off and see if the cable is still being pulled off stop.

A wire in the cable being broken can bind it.

Other codes may be a totally different issue.
'95 855 T-5R M, Panther - 22/28 mpg
'98 S70 GLT, Lil' Red 25/32 mpg
--------------------
Volvo's of past: '87 740 GLE, '79 262C Bertone, '78 264, 960's, '98 S70 GLT, '95 850 T-5R YellowVolvo Repair Videos
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RickHaleParker
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Re: chasing demons

Post by RickHaleParker »

Only shows up when it is below freezing. Moisture in vacuum line freezing...?
1998 C70, B5234T3, 16T, AW50-42, Bosch Motronic 4.4, Special Edition package.
2003 S40, B4204T3, 14T twin scroll AW55-50/51SN, Siemens EMS 2000.
2004 S60R, B8444S TF80 AWD.
2005 XC90 T6 Executive, B6294T, 4T65 AWD, Bosch Motronic 7.0.
mecheng
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Re: chasing demons

Post by mecheng »

Moisture on your cable causing it to freeze? I lubricate my throttle cable with white grease.
1998 Volvo S70 T5 - SE - 240km - Sold July 2018
1997 Volvo 850 GLT - 190km
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shegarty
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Re: chasing demons

Post by shegarty »

So it looks like something must have gotten jarred out of alignment or a spring stretched in my attempts to get her started the other day. I loosened the throttle cable from both ends and it moved freely, I threw some lube in it just for good measure. When I reattached it I found that using the fine adjustment to add a bit of slack to the cable did the trick. She is now back to a smooth idle at the appropriate rpm and she has been starting, so fingers crossed? In a couple of days and several starts I have not had any more codes pop, vacuum or otherwise. I'll be sure to post back if I do 😉 Thanks again for all the help and suggestions, you guys are awesome!
current - 98 S70 T5 SE (255k km)
previous - 90 745T (400k km - sold); 94 855 T5 - (206k km - blown timing idler bearing)
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