Is there a fuel pump for the Regina ignition in-tank pump setup that has a check valve? Or are there other solutions on Regina ignition vehicles?

I bought p/n 3507736 from FCP Euro, but it's very hard starting in the morning after sitting over night. The FAQ page only discusses the Bosch arrangement with the pump under the vehicle. I read that the Regina pumps are to have a check valve built into them, but this must not be the case on the pump I received.

I can turn the key on and off 6-10 times to pressurize the fuel rail, and then it starts right up. Otherwise, it's a lot of cranking before it fires.

I'm working on a 93 940 with Regina ignition and only one fuel pump which is in the tank.
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94 940 n/a 330k+ and rolling, owned 20+ yrs; 93 940; 89 780 turbo; 05 XC90; 07 S60 T5; sold 92 745T; sold 88 764T

Iiiiiiinteresting.....

I have this exact same problem. 1990 740 GL with a .... formerly Regina fuel system. It has a new bosch style pump installed, and that has a check valve in it.

I haven't opened up the trunk to check the tank pump because of the fumes involved. I suspect my late friend and owner of this car may have caused some issues in the tank too.

What is this fuel accumulator? Sounds like one of the anti-surge type things that damp the fuel lines and prevent resonance. The search function isn't working right now, so I'm not seeing anything on a search.

I believe Volvo calls it an accumulator. Some say it is a pulsation dampener, to smooth out the flow pressure to the fuel rail. One of my other make of vehicles has one on the rail and there isn't any vacuum conncted to it. Members on other Volvo forums claim that the accumulator becomes leaky and so it cannot hold the fuel in the lines and hence the long cranking attempts. For me , even after a start , I believe I was not getting the full pump pressure at the rails and this cause the stuttering and backfiring when I tried accelerating. I took mine apart and honestly , it looks like just a two chambered device with no moving parts inside. So where it leaks , I think, is at the attachment points. The device merely pushes on , at both ends , to the metal fuel line. The material there is rubbery and perhaps over the years it has lost its sealing ability.

I made a purchase of a fuel pump on Rock Auto that turned out to be a different design than the original pump. The gizmo on top of the pump would not fit, so I did not reinstall it. Little did I realize at the time how much trouble it would cause. I installed an after market check valve, but that burned the pump out. The pump burned out on the interstate, thankfully close enough to an exit to coast out of traffic, and cost me a $250 tow.

I have installed the correct pump, re-installed the gizmo, and now it starts just fine even after sitting overnight.
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94 940 n/a 330k+ and rolling, owned 20+ yrs; 93 940; 89 780 turbo; 05 XC90; 07 S60 T5; sold 92 745T; sold 88 764T

Gents , visiting here from the 700. I totally deleted that accumulator thingy from my fuel assembly and inserted a length of SUBMERSIBLE fuel hose in place . So far I am not having any issues like I did before . Drove me nuts having to "prime" the fuel pump a few times for starting , not to mention the backfiring and stuttering of the engine when accelerating. I searched on the internet and there were a few hits IIRC on the Swedish site. A few members there commented on not having any issues with the deletion , driving thousands of miles. Time will tell.

in the older cars with two pumps and the bosch system many had issues with the prepump and the symptom was it ran fine until they reached about 1/2 tank , Ive spoken to owners that didnt fix it but kep tthe tank full.. Yours is a different system but I;d just make a note that wheather the tank is full or low might make some difference..

If you do open the tank, I'd siphon it out into jerry cans first and take a flashlight so you can look for any crap in the bottom. You might seal the flashlight in a ziploc..

keep the old bulb style trouble light way far away, I had a friend that tripped on a trouble light, broke the bulb and he had a can of open gas he'd drained. I'll spare you from the nasty details, It instantly created a very bad and easily avoidable situation.

Dear Amazonphil,

Hope you're well and stay so. An LED flashlight with fresh batteries should produce more than enough light to make visible any debris on the tank's floor. The floor is a tad over a foot below the opening for the fuel send unit. The lowest part of the tank is straight-down from the fuel send unit's opening, so is easily inspected.

Uunless the gas is very old or otherwise contaminated, there's no good reason to drain the gas tank. Water in the gas tank can be removed by adding some "dry gas" (methanol). Alcohols (ethanol [drinkable] or methanol [poisonous]) bond with water, enabling the water to be "burned" along with the alcohol.

As you noted, draining the tank means handling gasoline, which is best avoided for the reason you cite.

Hope this helps.

Yours faithfully,

Spook

I have a 93 -940 also.Regina non turbo...fix 1 thing another fails,,I changed the fuel pump,,above tghe pump was a "fuel accumulator" which made it a bastard to get in & out of the tank. I look at other fuel assemblies for the same model & there is no accumulator,,so I took it off,& put a length of flexible hose,,car would start,,so I change the white fuel system relay under the dash*& it started right up?/ ran for an hour or so & then it konked out!!!
any idea s what the problem could be ??

The "fuel accumulator" gizmo is an essential component on the fuel pumps with Regina ignition. I updated my post, so see my update. Rather than try to jerry rig something, just re-install it as the factory had it.

I think it was Art Benstein mentioned this in another post I had on the same issue, and I foolishly did not consider the consequences of omitting this essential part. I really don't know how it works, but it does work.
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94 940 n/a 330k+ and rolling, owned 20+ yrs; 93 940; 89 780 turbo; 05 XC90; 07 S60 T5; sold 92 745T; sold 88 764T

It has been a long time since I worked on the 940 my late MIL drove. Nearly 20 years. The "gizmo" I found and puzzled over seems best explained as a device to smooth out the rapid pulsations inherent in the positive pressure roller pump. It seems too small to maintain rest pressure over the volume of the fuel delivery plumbing.

If I had your symptoms, that is, needing to run the pump for a length of time in the morning before cranking, I'd look into how the fuel pressure regulator maintains rest pressure. I know it is awkward to get a gauge to attach to the Regina fuel rail, but this is your diagnostic approach short of swapping parts.

Another way for rest pressure to leak is via injectors flooding the intake manifold and whichever cylinder is open to it during rest. Either condition, fuel returning to the tank or flooding the manifold, will cause long crank times, but the leaky injector(s) will add the symptom of rough running at first.

Notes on Replacing a Regina Fuel PUmp and Why
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Art Benstein near Baltimore

"In the midst of winter, I finally learned that there was in me an invincible summer." -Albert Camus

my 740 had a stuck open injector so it would dump the fuel rail into cyl 3 upon each shutdown. upon startup a bit of a white cloud for a block or so until the cylinder cleared.

I didn't have the guage but found it by pulling the fuel rail, connecting it up unplug the coil high tension lead. , crank a it a bit then shut the key off and look. In my case injector 3 spewed a bunch of gas after key off which proved it was leaky. replaced 1 injector, all fine now. If you pull the fuel rail get new rubber O rings first. remember the safety risk since you will be spraying a bit of raw gas out from the injectors.

Regina is foreign to me, but it still has injectors so I don't see why this test would be much different. most shop manuals say to use the pressure gauge and assume you have one, That's safer because you don't need to spill any raw fuel out.

I think if you do this and apply safety precautions it will prove to you if all your injectors are shutting off and then you can forget about that if they do or fix it if they don't all shut off. It will prove either way then you can move forward to other troubleshooting. Knowing the actual fuel pressure measured with a gauge has some value, this only proves if they shut off or not.

the relay might have bad contact points, if so that could cause intermittent pump operation. I took an old relay and added a fuse and jumped the contacts so if I swap that relay in it powers up my fuel pump , only for testing.
in a pinch you can pop poen the cover of the relay and inspect or clean the contacts. if they look all burned, change the relay.

If I replace a fuel pump I also wire in a low watt bulb in parallel with the two pump wires. it gives me a easy way to monitor if the pump has power or not to help diagnose that easier. you can put the little indicator lamp where you want to. If I have any starting issue I can see if that lamp is on or not and that helps me with a more easy diagnosis especially if Im not near my tools and on the road somewhere. The last one I did I just shared the connector at the pmp since I had to solder new lugs ont he pump wires anyway, it might be neater to pick up those same two wires right at the relay, then its in the cabin. I just put mine under the hood near the brake reservoir.

a test for the older system , you can pull a fuse to omit the in tank pump. then open the fuel line and see if it fills a jar and how fast. you can do the same with the main pump running and see more flow.. I assume you can do a similar test with the regina but maybe it only has one pump..
if you do this realize the pump can move a lot of fuel quickly so dont flood the jar all over the place and do not cause a fire.

pressure requires resistance to flow, best to use a gauge for that. If you can find stats on the gallons per minute of flow then you can measure the flow rate. you can likely just guestimate..

the filter screens in the older ones often turn to plastic garbage. Im working on an car right now that sat a while and the bottom of the tank has a lot of thick tar-like goo. Its like molasses.. that stuff can sit in the tank and plug up filters and screens things. the pump might make considerable pressure but if the inlet gets blocked it can get stuck cavitating, and no flow then. in my case the screen will be plugged and Ill have to flush the tank with solvents so I plan to use the old fuel pump as my solvent flush pump to rinse this garbage out of my tank, and then I will replace the pump and the filter. Ill also clean the fuel line maybe by pulling a wire and then thin rope through it or similar. I don't want that molasses like goo in the injectors..


I'd suggest checking your fuel flow first, if you don't have fuel delivery issues you may not want to muck with the tank. on the earlier cars they had a filter screen and the pump in the tank and I'd change both if I go there..

Dear rjritterjr92,

Hope you're well and stay so. Volvo #3507736 is the correct fuel pump for 940s with Rex/Regina ignition/engine management. This in-tank pump does not have a "check valve" and there's no obvious place to retrofit one.

Volvo VADIS - a superseded dealer parts/service database - has fuel system diagrams and parts lists. These show that 940s with Bosch ignition/engine management - up to and including the '94 models - have a dual pump system with a check valve. These models have an in-tank pre-pump and a main pump mounted on the under-body.

In 1995, 940s with Bosch ignition/engine management have a single in-tank pump. There is no check valve.

I recite these things to make the point that single-pump fuel systems - Rex/Regina and Bosch - have no check valve. I've a '93 940 with Rex-Regina ignition/engine management. It cranks for 2-3 seconds and runs smoothly. I've replaced the in-tank pump with Volvo #3507736. The same is true of a '95 940 with a single, in-tank fuel Bosch fuel pump.

I suspect the reason your car does not start promptly is a failed/failing fuel pump relay. If this relay is the factory-original item - there should be a date on it - it is past the end of its service life. It is white, rectangular, so easy to find on the fuse/relay block, behind the front center console ashtray.

Hope this helps.

Yours faithfully,

Spook

To check Spook’s suspicion about the pump relay you can connect a volt meter or test light to the pink pump wire in the trunk. Apparently the pump works OK when you repetitively prime it BEFORE cranking the starter. But it’s hard to hear the pump when the starter is cranking. The volt meter or test light will tell you if you’re getting power to the pump DURING cranking, Lack of voltage to the pump during cranking could be caused by various things - like a bad relay, a weak battery that’s sapped of too much power while cranking, weak impulses from the crank position sensor, to mention just a few.
The one and only time I replaced a Regina pump I failed, on the first attempt, to get the pump properly locked into the sender unit bracket so the line pressure just above the pump pushed it downward, causing a large leak and very difficult starting.