98 S70 T5: Starts, lugs, dies Topic is solved

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WhatAmIDoing
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98 S70 T5: Starts, lugs, dies

Post by WhatAmIDoing »

Drove the car Monday, parked, all was good. Tuesday afternoon, I turned the key, motor turned over and fired right up, but then it couldn't make it to idle. It lugged on for a few seconds before I turned the key back off. Counted about 2 fires per second. I looked around the engine and under the car, but didn't notice anything. Tried starting it again, and same thing happened only even weaker. I tried giving it gas, but made no difference and engine died (all within 15 seconds from start up). Engine then refused to start. Ambient temperature was 32C. Tuesday night, I saw a small spot of oil (about the size of a silver dollar). I believe it was oil at least, stained paper towel light brown like oil does, but had no smell and felt thin like water. It looked like it was dripping off something behind the transmission. Car has never left oil spots on the ground since I've owned it.

This morning, ambient temp was 13C, car fired right up and idled as usual. Oil spot did not look much bigger and I could not see any fresh drips. Oil level had not dropped noticeably since I checked last week or on Monday. The coolant has been slowly creeping towards the min line for the past few weeks, but I have not noticed any coolant drips (WP is not leaking as far as I can tell). Not sure if this is really related. I know there are hundreds if not thousands of possibilities here, but I have no idea where to look. I'm taking the car to the local recommended indie on Friday, because I feel this is over my head.

I had a similar problem during the winter where the car would not start, or would start, run for a couple seconds, and then die. Plugged in the backup fuel relay the PO had in the glove box and then it would start right up. However, when the backup relay got too hot (in traffic / long trips) engine would suddenly die. Restarting resulted in a really rough idle for several minutes and then the engine would eventually recover for a while (and repeat). Bought a new fuel pump relay, and this fixed the issues. I'm not sure this is related either, as my experience on Tuesday was far from identical.
'98 S70 T5M - 282,000+mi - forever a project
'99 S70 "AWD" - 220,000+mi - part out :cry:
Knows enough to be dangerous :wink:

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theWIFES_S70
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Post by theWIFES_S70 »

The drop in coolant is troubling... But that could be something like a drip from the petcock. (Which is what I have.) Or a small leak from a hose somewhere. Could also be the heater core... I think I read somewhere on here about someone who only lost coolant when he would "boost." Hopefully the Turbo folk will chime in. I have read that the million turbo hoses are all super sensitive and a leak or break in any will make the car feel like it's on the outs. Have you had the opportunity to inspect them all?

Your fuel pressure relay gets too hot and then your car stops working? How do you know this? Do you swap out relays when the car overheats and it fires right up with a "cooler" relay? That's an odd one. I haven't read about that one. Are you using Volvo relays and are they new/newish?

Also, did you get any codes? When I got a P0117 and P0118, the car would not turn on until I replaced the Engine Temperature Sender.
1998 Volvo S70, N/A, 5-speed, 185K
2007 Volvo S40, 2.4i, 5-speed, 100K

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Post by WhatAmIDoing »

I would not be surprised if the coolant leak is the radiator, heater core, or any number of hoses. Even the reservoir tank has some hairline cracks in it (was planning on replacing soon). At 20 years old, that leak could be anything. I only started paying more attention this past week because it was nearing the min line.

I tried to check the all the hoses I know about (I'm sure there are more). There have always been oil stains/old residue on top of the turbo, but I noticed no fresh oil. I cannot get a good look under the car. I cannot source the leak. I've been doing a lot of city driving recently and haven't had much chance to get into some boost.

The fuel relay is a long story of discovery. When it got cold out (under 4C), the car would not start, and I would not hear the fuel pump kick on. The PO gave me a spare fuel relay (KAE) and said they were known to go out in the cold. I swapped them out and the car started right up. All was good until I went on a 300mi highway road trip at -5C. All was good, at the 80ish mile mark hit traffic and inched for over 30 minutes. When it was time to go, I stepped down on the accelerator and... nothing happened. I rolled to the side of the road and turned off the engine. Popped the hood and inspected the throttle and cable. Started the engine and it idled rough, pressing the throttle did nothing. Let it idle for a while, and eventually it roared back to life. This happened 4 more times, but while driving at highway speeds. I still had the original fuel pump relay, warm and toasty, in the glove box, so I swapped them back. Drove beautifully, uninterrupted for the remaining 200 miles. As far as I know, this is the same Volvo relay from the factory. As long as the stock Volvo relay is warm, it works.

I bought a new KAE fuel pump relay from FCP in January and drove over 1000 (maybe 2k now) miles without problems in various temp ranges until this week.

My rear O2 sensor is not plugged in because it's too short for the aftermarket exhaust the PO installed. So I get codes for downstream O2, upstream O2, MAF airflow sensor, and some other emissions code. I do not have a scanner, and there are no parts stores near by that offer this service for free (like really?). I assumed the MAF and upstream O2 were fine, or else the car wouldn't run at all, and that's also what the last store clerk said when he pulled the codes.
'98 S70 T5M - 282,000+mi - forever a project
'99 S70 "AWD" - 220,000+mi - part out :cry:
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Post by wizechatmgr »

Fuel relay that's hot - happen to check and/or replace your fuel filter recently? Is the fuse the correct rating for the fuel pump/injection? I believe these relays to be good for ~30 amps based upon my last disassembly.

Abscate and I replaced my fuel filter about a month or so ago. All of my intermittent starting issues haven't returned.

My failure to start modes were as follows:
Car starts, runs 2-3 seconds shuts off, repeat process a couple times and it stays running
Car would start and run 2-3 seconds but not start after that. An hour or two later it would fire right up
Car wouldn't catch but turned over with ease (no fuel) - sometimes it would start if i put my jumper wire on, other times not. It always sounded like the fuel pump started.
Car would not pick up speed and lacked the power I believed it should have but usually ran great cold (And in combo with a new Turbo Control Valve it now has enough power to be scary...)
During none of these occasions did the tail pipe smell like fuel - this lead me down the lack of fuel route.

I have a new fuel pump relay but haven't installed it yet. There are also some relays on my 99 that are aging and in need of replacement - namely the starter relay and the main relay. Both were starting to show heat cooking them when removed and inspected. I'd suggest checking every relay you can get your hands on for cooking (blackened or blued terminals or case melt/deformation)
Wisdom requires knowledge as a prerequisite, but knowledge can be developed due to a lack of wisdom.
In order to learn how to fix something, you must first learn how to break it.
1999 V70 XC AWD 2.4 T -- ~193k miles
1998 V70 2.4 NA -- ~180k miles

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Post by wizechatmgr »

As far as O2 goes - I believe she goes into Limp mode if she doesn't have both sensors giving signals in the proper range (someone senior to I can confirm/deny this) and I believe the MAF would have to be semi-decent to start if hooked up.

Coolant doesn't take much of a leak and sometimes is impossible to find just by smell. Would suggest a UV reactive dye and a UV light source to track that down. Obviously if you are able to smell it you'd know roughly where to look. My 99 had a coolant expansion tank that developed a crack at the bottom rather close to the lower hose barb. It would be fine and I didn't smell coolant at first. It would go down a little but not alarmingly so. Then it really started leaking to the point I could find it -- all happened within ~2 weeks and of course with snow coming down.
Wisdom requires knowledge as a prerequisite, but knowledge can be developed due to a lack of wisdom.
In order to learn how to fix something, you must first learn how to break it.
1999 V70 XC AWD 2.4 T -- ~193k miles
1998 V70 2.4 NA -- ~180k miles

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Post by WhatAmIDoing »

I just acquired a new Bosch fuel filter, but have not had a chance to install it. I was not in a hurry to replace because the PO said it was replaced when he did the fuel pump at 210k. Makes me wonder if he replaced the fuel pump, filter, and relay because he was experiencing these issues. I will try replacing the fuel filter asap, too bad I have 3/4 of a tank.

I will try checking all the relays when I get the time. I checked all the fuses and insured their amperage matched the fuse box cover when I bought the car. Based on what I read, the forum consensus was that the downstream O2 sensor did not have any real effect on performance. It's been unplugged for the duration I owned the car, and flooring it can get scary. :o That does not sound like limp mode.

I'm looking at ordering a new reservoir tank. I'm going to have to flush the cooling system anyway as I do not know what is in there already.
'98 S70 T5M - 282,000+mi - forever a project
'99 S70 "AWD" - 220,000+mi - part out :cry:
Knows enough to be dangerous :wink:

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Post by WhatAmIDoing »

Replacing the distributor cap and rotor this week along with the fuel filter. Will report back after a few weeks of driving if this solved the problem.
'98 S70 T5M - 282,000+mi - forever a project
'99 S70 "AWD" - 220,000+mi - part out :cry:
Knows enough to be dangerous :wink:

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