98 v70 T5 An odd hesitation

Post by **timmybdaddyof3** » 06 Sep 2014, 22:21

I have had the car for about a month and 2000 miles and last week it started acting a bit screwy....its been 40k since the last minor tune up (plugs, cap and rotor) and i am getting ready to order parts for it on Monday, but wanted to run this by you guys to see if I should be looking at additional things.

First off it only occurs when heat soaked...stopping at a red light after a freeway run, or upon restarting after sitting for less than an hour...and it typically only occurs once per heat soak incident. Step on the gas, rpms climb to ~1500, and the move out is VERY slow...doesn't matter how deep you bury the throttle, it will take the upwards of 2 seconds to climb from 1500 rpm to 2k, and then all is normal. If you go WOT there is this lag, and then its almost like it goes into full boost and will pull hard enough to engage the tracs system. There is no noticeable misfire or stumble, there is just no power, and its like once it "clears its throat", everything returns to normal.

As a side note, and based on my experience with turbo-charged cars this is somewhat normal, in general there is minimal power below about 2800 rpm once you cross that threshold she pulls like a train.

As of right now there does not seem to be any vacuum leaks (replaced all the lines and elbows with quality rubber, but have not done anything with the oil can yet), visually inspected the turbo plumbing and it looks good (although looks can be very deceiving). Planning on ordering a new MSD coil (this one has 100k on it), Volvo plugs, Bosch cap and rotor, Bougicord wires, Mann filters (air, oil and fuel) and Samco cooling and IC hoses.

Anything else I should be looking at or that I am missing? And are there any other upgrades I should be considering besides the coil while I am in there (I am considering ordering injectors because I cannot find a receipt showing any kind of change or service (and I have everything down to the original window sticker) I have a little trouble believing that she has 280k on these injectors and still averages 22 MPG with the way i have been driving her)

Thoughts.....

Rbaratt · Post by **Rbaratt** » 07 Sep 2014, 08:05

Does this vehicle have coil, wires, cap and rotor? My 2000 S70 has coil packs and I thought the 99's would also have them...but I am not sure when the change was made.

Post by **abscate** » 07 Sep 2014, 10:17

My November 1998 built 1999 T5 has coil packs

If you have ETB ( and an ETS light on dash) it has coil packs... No cap, rotor , plug wires, or coil - on- fender

Post by **timmybdaddyof3** » 07 Sep 2014, 15:12

That was a "late night too tired" typo....car is a 98 and is cap and rotor...sorry for the confusion.

It honestly does not feel like an ignition issue; from the "butt dyno" it feels more like seriously retarded timing. After doing some research i am questioning if it is not the IC getting heat soaked and the computer dialing the motor back...once the vehicle starts moving a bit things return to normal. Being that I am in AZ and temps have been around 105 pretty much all the time when it occurs.

This may sound a bit insane, but as I am thinking about installing a boost gauge anyway I may install a gauge for charge air temp along with a heavily controlled water/meth injection system (not so much for the extra performance more for the fact that I am sure the air that is being compressed is already at 150* and only goes up from there) . On my Modified Audi 200q20v I had a similar issue but it would fall flat on its face and not even idle after a high speed run or restart when seriously hot...between a leak in the IC hoses, and high charge air temps the problem was resolved.

I really don't want to start big mods to this car until i get this one solved.

Post by **mecheng** » 07 Sep 2014, 16:46

Yes it's true all cars dial back especially when really hot. I would do the following to start
Because Arizona is damn hot. I visited Phoenix and it was deserted, I think everyone was inside. So damn hot. I liked hiking in Tuscon... Anyways:

- make sure you are running premium
- use a 60/40 or 70/30 coolant mix and flush rad with distilled water
- make sure the fins on your inter cooler and rad are clean, use garden hose and remove bottom shroud to clean intercooler
- clean your engine bay, dirt prevents heat loss by convection
- in stop and go you will get heat soke, go easy on her until you get moving
- relocate your horns

Then look into water injection or bigger FMIC

Post by **timmybdaddyof3** » 07 Sep 2014, 22:04

thanks for the thoughts....I am about 90% sure that's what it is. Ambient temps have been around 105*, and it seems like as soon as air starts moving things become normal...anyone have any idea how much air the stock fans move? I know it is doing its job as my temp needle climbs to 3:00 and rarely moves to the mark above it, but i don't believe there is such a thing as too much air flow and am thinking a new electric might be a good thought.

Post by **jblackburn** » 08 Sep 2014, 14:47

My S70 was a pig when it was heat-soaked in the summer. What you are describing is completely normal - lots of knock occurs between 1500-2000 RPM, and it pulls power/ignition timing severely to keep it from happening.

The drawback to forced induction...the Cruze does it too.

The fan is already drawing air over the front of the car at a stop when the AC is running...however, the intercooler is sandwiched in between a hot radiator and a hot AC condensor. It's doing nothing but pulling really hot air over everything.

Run 91/93 octane at all times in the summer (10% ethanol helps over 0%, believe it or not - the formulation of ethanol keeps knock down). Make sure the plugs are gapped correctly as well.

Post by **timmybdaddyof3** » 08 Sep 2014, 21:35

pretty much confirmed it is heat soak...I always run premium, but today was the first day since i have owned it where the temps were in the high 80's (its been 105-110)....no issues at all where they normally would have been. Been logging odb2 live data and it does show it dialing back timing when it occurs; today it didn't happen that way. I am thinking a bigger intercooler, meth injection and a charge air temp gauge just got added to the shopping list

Post by **jblackburn** » 08 Sep 2014, 21:41

A FMIC alone might alleviate a lot of the problem. You could heat-wrap the turbo pipes as well to keep them from heat soaking in the hot engine bay at a stop.