Sudden Hesitation and Stalling 1999 V70R

[scot850]

13.8-14.2V with the engine not running? That is what I hope for with no load with engine running.

12.6V should be fine for starting assuming the battery does not have a bad cell. I would expect the pump to prime if it has been standing for some time. It only runs for a short time as it prime the pressure. Replacing the fuel relay with a jumper and switching the ignition to II you should hear the pump running constantly. If you hear nothing and you are not getting pressure at the rail, the pump is either not getting 12V or is dead.

Neil.

[Vova585]

I disagree on the testing method and also on the fact that current battery is not enough and you need to to buy a new one asap. First of all testing with multimeter will not give you true information if wires are able to carry current. You need to test it with 5amp test light. Take old headlight bulb of 55w and connect 2 wires to it. Then disconnect the connector where you currently testing and gently front probe it. Cycle key and see if the bulb is bright(will be hot, so be mindful of that). If it is bright, you need to inspect down the line. I think you need to cut a piece of metal around the pump(it's been years I had 98v70xc) to inspect it further. I belive the proper way is to drop the suspension and tank, so too much hassle. I believe I cut opening with either dremel tool or big metal cutting scissors. After you remove the pump you will be able to bench test it(likely it is shot) and replace with reputable brand propartssweden, pierburg, bosch. Replace fuel filter. Assemble it all back(can use some thin metal and rivets to cover the hole+ some auto seam sealer around )and enjoy your ride
P.S also please try not to front probe with thick test leads. It is better to take 2 T pins and backprobe. You are risking to spread the connectors two wide so in a future when you will put it together you might have intermittent loose connection due to weak pin tension.

Here is master class from Eric O

[Sveedy]

I think you might be right about that voltage Neil. I'll have to check mine when I go out today and see if that voltage is when I start the car or just before.

[claymanshu]

Hello all, I'm finally posting an update and providing closure on this issue. Upon further inspection, there was an access panel already cut in the floor for the fuel pump. The pump (which apparently been updated to a 340 LPH AEM unit) had slipped out of its tube, such that it was not pumping to the rail; fit it back together and the car fired right up! I still need to find a better way to secure it in place, but I'm very happy to have found the culprit.

Thank you all for your knowledge and time, it certainly helped keep me on the right track.

[Vova585]

Great many thanks for update. My old friend was always saying " better is the worst enemy of good" . If this happened to you ones, chances are it will possibly happen again. I would look for instruction for AEM UNIt instalation. Maybe previous owner missed a part or a step. If all looks legit, identify area of weakness and try to correct it. If no way to correct it-save yourself nerves and go to local junk and get oem setup and install it there(chances are there would be an opening made already). This is not 2JZ-GTE Supra so expectations should be reasonable as well. This car still has awd ir it is only fwd? Angle gears and collar sleeves are not cheap or easy to come by, so I see no point in "performance " parts that can leave you on a road stranded. Glad you found the issue.

[misha]

13.8-14.2v is at idle when engine is running.
12.6-12.7v is 100% charged battery,on rest,at least 2 hours after engine is turned off.

[claymanshu]

Great many thanks for update. My old friend was always saying " better is the worst enemy of good" . If this happened to you ones, chances are it will possibly happen again. I would look for instruction for AEM UNIt instalation. Maybe previous owner missed a part or a step. If all looks legit, identify area of weakness and try to correct it. If no way to correct it-save yourself nerves and go to local junk and get oem setup and install it there(chances are there would be an opening made already). This is not 2JZ-GTE Supra so expectations should be reasonable as well. This car still has awd ir it is only fwd? Angle gears and collar sleeves are not cheap or easy to come by, so I see no point in "performance " parts that can leave you on a road stranded. Glad you found the issue.

Hi, thanks for the quote, good to keep that in mind with this car in general. It's already happened again; this time I was ready with the tools on the side of the road. The car is FWD now with an M56, so fortunately the angle gear and supplemental components are gone. Haven't had luck finding an installation manual for that AEM unit yet. It looks like the rebuilt unit from Vast is using two o-rings.

https://vasttuning.com/product/p80-awd- ... -assembly/

[scot850]

That Vast tune AWD pump is a great addition to AWD owners. Price is not terrible either.

Neil.

[Vova585]

That Vast tune AWD pump is a great addition to AWD owners. Price is not terrible either.

Neil.

I would defer to Neil on this one since it looks like he walked this road before. viewtopic.php?t=72252.

I would just ask boring questions: what is the end goal for this car(ultimate sleeper, track fun, daily commute, car show)? How much funds you are willing/able to elocate towards this car? What if this issue will happen with the full tank of gas?(as far as I remember fuel pump lines and screw cap are located below the top level of the tank and you might spill 3-4 gallons of fuel on the side of the road..If enviromentals will see you or there would be spark...). Old volvo will provide you with endless possibilities to satisfy your inner mechanic itch and would try to drain your wallet while doing so. Unless this is a track or sleeper car I would return to stock and don't touch it again for hopefully 10 years(you are in CA so maybe even longer).

[claymanshu]

The car is definitely a sleeper right now. I would like to be able to daily drive it (or at least weekly!). Unfortunately the OEM fuel pump is NLA and I've read that the ProParts Sweden replacement is unreliable. The root of my issue seems to be the totally shot suspension in the rear, such that the car is frequently hitting its bump stops, thus shaking the pump loose. I'd be okay with replacing the AEM pump with an OE version (Bosch for FWD, Walbro for AWD) but based on the design of the housing I'd be worried about it shaking loose again. I'm going to try to fit a small tube with clamps between the outlet of the pump and inlet of the housing as a modification.